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section "Plants"
Questions that require a detailed answer.
1. The process of photosynthesis occurs intensively in the leaves of plants. Does it occur in ripe and unripe fruits? Explain your answer.
2. What signs are characteristic of conifers?
1) propagation by seeds that lie openly on the scales of cones
2) fertilization does not require an aquatic environment
3) leaves are scaly or needle-shaped, covered with a waxy coating
3. What are the main differences between mosses and ferns?
1) have neither roots nor rhizomes.
2) in mosses, the haploid phase of development (gametophyte) predominates over the diploid phase (sporophyte). Sporangia of mosses are boxes with spores, and in ferns they are sori located on the underside of the leaves.
3) lowly organized mosses do not yet have division into organs. More organized bryophytes have rhizoids, stems and leaves.
4) ferns have rhizomes, stems, leaves, and fully formed conducting tissues
4. It is known that in sphagnum bogs, despite the large amount of moisture, water is inaccessible to many plants. What is this connected with?
2) the growth of roots is also hampered by acidification of the water and soil of the swamps;
5. What is the nutritional feature of unicellular algae?
The peculiarity is that they are able to absorb dissolved organic substances through the pores of the shell.
6. What characteristic features of plants do you know?
Characteristic characteristics of plants:
1. Plant cells are covered with a thick, dense cellulose cell wall (wall) that gives them their shape.
2. Cells contain plastids, which contain the green pigment chlorophyll. This is a photosynthetic pigment.
3. Plants are characterized by the process of photosynthesis - the formation of organic substances from inorganic ones using solar energy. Therefore, according to the method of nutrition, most plants are classified as autotrophs.
4. Plant cells contain vacuoles with cell sap; they regulate the osmotic flow of water into the cell, and they also accumulate reserve nutrients and metabolic products of the cell.
7. What is the importance of photosynthesis for life on Earth?
1) photosynthesis provides all living organisms with the organic substances they need.
2) during photosynthesis, light energy is converted into chemical energy available to living organisms.
3) in the light phase of photosynthesis, a by-product is released - molecular oxygen, which is necessary for respiration for most organisms.
8. Why do many seeds not germinate when there is excess water in the soil?
1) When there is an excess of water in the soil, there is a lack of oxygen, which is necessary for plant respiration.
2) The germinating seeds of most plants receive a significant part of their oxygen from the free spaces of the soil, and not from water.
9. Why did angiosperms become dominant on Earth?
1) the life forms of angiosperms are represented by trees, shrubs, and herbs, which determines their greatest ecological plasticity.
2) vegetative organs (roots, leaves, shoots) have numerous modifications and
3) are the most specialized in structure and functions.
4) angiosperm seeds are protected by the pericarp, which contributes to their better preservation and distribution.
5) fertilization does not require water, and pollination methods are very diverse (insects, wind, self-pollination, etc.).
6) they are spread by wind, water, animals or humans.
10. What role do stomata play in plant life?
1) stomata - a highly specialized formation of the plant epidermis, consisting of two guard cells and an intercellular space (stomatal fissure) between them.
2) transpiration and gas exchange occur through the stomata. Transpiration is the evaporation of water by a plant.
3) transpiration regulates water and temperature regime plants.
11. How can you explain that multicellular plants consist of several types of tissues?
1) with the advent of multicellularity, different functions appeared in plant organs, and these functions could only be performed by special formations - tissues.
2) it is necessary to conduct substances to organs located far from each other; this is done by conductive tissues.
3) excess substances accumulate in the cells of the main tissue, etc.
12. It is known that before transplanting young plants into the ground, they are picked (the tip of the main root is plucked off). Why do they do this?
1) when picking plants, the growth of adventitious and lateral roots is activated;
2) due to the increase in the total number of adventitious and lateral roots, the mineral nutrition of the plant improves, which stimulates its growth.
13. Find errors in the given text, correct them, indicate the numbers of the sentences in which they are made, write down these error sentences.
1. A flower is the reproductive organ of angiosperms.
2. The flower is a modified leaf.
3. The functions of a flower are sexual and asexual reproduction
4. The flower is connected to the stem by a peduncle.
5. A flower has pistils and stamens.
1) a flower is a modified shoot;
2) a flower is an organ of sexual reproduction and has nothing to do with asexual reproduction;
3) not all flowers contain pistils and stamens; there are dioecious ones (pistillate and staminate flowers), in addition, there can be only one pistil in a flower.
14. When potatoes were introduced into culture, potato riots arose in Russia. Why did the peasants not want to grow this plant?
15. What are the main structural features of plant cells?
1) the presence of a rigid cellulose cell wall;
2) the presence of vacuoles with cell sap;
3) the presence of plastids.
16. What are the main distinctive features higher plants compared to lower ones?
1) adaptability to reproduction in a terrestrial environment;
2) the presence of well differentiated tissues and organs;
3) multicellular reproductive organs.
17. Find errors in the text, indicate the numbers of the sentences in which they were made. Explain them.
1. There are two divisions of angiosperms: monocotyledons and dicotyledons.
2.Dicotyledons evolved from monocotyledons and they have many common features.
3.The embryo of dicotyledons consists of two cotyledons.
4.Leaf blades of dicotyledons usually have parallel and arcuate veins.
5.Monocotyledons usually have fibrous roots, a three-membered type of flower structure.
6.These are mainly herbaceous plants.
18. Gardeners, when picking cabbage seedlings, pinch the top of the main root, and when propagating currant bushes, they use stem cuttings on which adventitious roots develop. Both of these flowering plants belong to the class of dicotyledons. Explain what type of root system will be in cabbage grown from this seedling, and what type of root system will be in currants grown from a stem cutting.
Response elements:
19. The flowers of many angiosperms are pollinated by insects. Explain the mutual benefits of cross-pollination for insects and plants.
Response elements:
1) For plants: thanks to insects, the probability of pollination increases, the possibility of offspring acquiring new characteristics increases (variability and better
20. What tissue of flowering plants connects its organs into a single whole?
Conductive tissue (xylem and phloem)
21. What features are characteristic of angiosperms?
Response elements:
1) the presence of a flower
2) the presence of fruits with seeds
3) double fertilization
4) a wide variety of ecological forms and groups
23. What is the purpose of whitewashing the trunks and large branches of fruit trees?
To protect against sunburn and from pests.
24. What features are characteristic of the plant kingdom?
1) The presence of chloroplasts in cells in which photosynthesis occurs
2) The presence in the cell of a cell membrane and vacuoles with cell sap
3) They grow throughout their lives, most do not move from one place to another.
25. Find errors in the given text. Indicate the numbers of sentences in which errors were made and explain them.
Answer elements: errors were made in the sentences:
1) 2 - among fungi there are also unicellular ones, for example, yeast;
2) 3 - there are no autotrophs among fungi (since their cells do not have chlorophyll);
3) 4 - the cell walls of fungi consist of chitin, not cellulose.
26. Name at least 3 features of land plants that allowed them to be the first to develop land. Justify your answer.
Response elements:
1) the appearance of integumentary tissue - epidermis with stomata, which helps protect against evaporation;
2) the appearance of a poorly developed conducting system that ensures the transport of substances;
3) development of mechanical tissue that performs a supporting function;
4) the formation of rhizoids, with the help of which they were fixed in the soil.
27. What processes ensure the movement of water and minerals throughout the plant? Explain your answer.
Response elements:
28. Why does plowing the soil improve the living conditions of cultivated plants?
Response elements:
29. What are the characteristic features of the fungal kingdom?
Response elements:
1) the body of fungi consists of threads - hyphae, forming a mycelium;
2) reproduce sexually and asexually (by spores, mycelium, budding);
3) grow throughout life;
4) cell membranes contain a chitin-like substance, a reserve nutrient – glycogen.
30. Explain through what tissues and how substances are transported in angiosperms.
Response elements:
31. Find errors in the given text, correct them, indicate the numbers of the sentences in which they are made, write down these sentences without errors.
Response elements:
32. In the 17th century, the Dutch scientist Van Helmont conducted an experiment. He planted a small willow tree in a tub of soil, after weighing the plant and soil, and only watered it for several years. After 5 years, the scientist weighed the plant again. Its weight increased by 63.7 kg, the weight of the soil decreased by only 0.06 kg. Explain why the increase in plant mass occurred, what substances from the external environment ensured this increase.
Response elements:
33. What is the difference between root vegetables and root tubers?
34. What is the significance of leaf fall for mid-latitude plants?
What are the distinctive features of brown algae?
Response elements:
2) the main storage product is kelp;
3) in life cycle there are mobile stages;
4) everything brown algae multicellular.
35. What methods of dispersal of fruits and seeds exist?
Response elements:
1) with the help of the wind;
2) using water;
3) with the help of animals and humans;
4) self-spreading.
36. How do the embryos of dicotyledonous and monocotyledonous plants differ?
Response elements:
1) in dicotyledons, the embryo usually has two cotyledons, in monocotyledons - one;
2) in dicotyledons, the embryo is symmetrical - the bud occupies the apical position, and the cotyledons are located on the sides of the embryo; in monocots, the embryo is asymmetrical - the cotyledon occupies the apical position, and the bud is located on the side;
3) in dicotyledons, cotyledons usually germinate aboveground, in monocotyledons - usually underground.
37. B what does it consist of ecological significance nodule bacteria for plants?
Nodule bacteria form a symbiosis with leguminous plants and participate in the fixation of atmospheric nitrogen into mineral compounds available to plants.
38. Why are lichens very hardy?
The endurance of lichens is explained by the possibility of both autotrophic and heterotrophic nutrition, as well as the ability to fall into a state of suspended animation, in which the body becomes severely dehydrated.
39. How does a person use bacteria?
Response elements:
1) in wastewater treatment plants;
2) in everyday life and the food industry;
3) in microbiological synthesis;
4) to obtain a number of medications.
40. How do mushrooms differ from plants?
Response elements:
1) heterotrophic mode of nutrition;
2) storage nutrient glycogen;
3) the presence of chitin in the cell walls.
41. What is called double fertilization?
42. Name distinctive features the fungal kingdom from the plant kingdom.
Response elements:
1) fungi are heterotrophs, not capable of photosynthesis
2) fungi differ in their cellular structure: they do not have chloroplasts, the cell wall contains chitin, and the reserve nutrient is glycogen;
3) the body of fungi is formed by hyphae.
43. Why were psilophytes the first to colonize land?
Response elements:
1) the appearance of integumentary tissue - epidermis with stomata - facilitating protection against evaporation;
2) the appearance of a poorly developed conducting system that ensures the transport of substances;
3) the appearance of mechanical tissue that performs a supporting function;
4) the formation of rhizoids, with the help of which they were fixed in the soil.
44. What harm does the tinder fungus cause to birch?
45. What are the similarities and differences between the fruits of plants of the Asteraceae family and the Poaceae family?
Response Elements: Common Features:
1) single-seeded dry indehiscent fruits;
differences:
2) in cereals the fruit is a caryopsis, and in Asteraceae it is an achene;
3) in the caryopsis, the seed coat fuses with the pericarp, and in the achene, the seed lies freely, the fruits may have tufts, parachutes, and trailers.
46. Name the adaptations of plants to life in dry conditions.
Response elements:
47. Find errors in this student's answer and comment on them.
Plants of the Legume family have a regular five-membered flower, a fruit pod and a fibrous root system.
Response elements:
1) moth flower, five-membered, irregular: unpaired petal sail, paired oar petals and fused petals - boat;
2) tap-type root system;
3) the fruit is a bean, not a pod.
48. What is the significance in the life of plants of beekeepers placing hives in buckwheat fields?
Prove that the lily of the valley rhizome is a modified shoot.
Response elements:
49. What is the significance of various flowers in the inflorescences of plants of the Asteraceae family?
Response elements: different types Flowers in the inflorescence of Asteraceae perform various functions:
1) attracting insects - false tongue and funnel-shaped;
2) seed formation - tubular and reed flowers.
50. Explain why seedlings do not develop when small seeds are sown at great depths.
Small seeds contain little nutrients, not enough for the seedling to reach the soil surface.
51. What structural features of the fruit - the drupe - ensure the distribution of seeds of many representatives of plants of the Rosaceae family?
Response elements:
1) drupe - a single-seeded fruit with brightly colored juicy pulp, which attracts animals;
2) drupes are eaten by birds or mammals, while the seeds, covered with the lignified part of the pericarp, are not digested in the digestive canal of the animal and are removed out with droppings
52. Why does potato yield increase after hilling?
53. In what life processes of plants does water participate?
54. Why can lichens live in barren places where other organisms cannot survive?
Lichen is a symbiotic organism. Its body (thallus) consists of a fungus and algae. Lichens can grow on stones, on walls, on sand. They don't need soil. The hyphae of the fungus absorb moisture from rain, dew and fog with their entire surface. Single-celled algae containing chlorophyll produce organic substances through the process of photosynthesis.
55. Why did the emergence of plants from water onto land become possible with the advent of tissues?
On land, the living conditions of plants are more severe than in water. To adapt to them, specialized tissues are needed. Thus, mechanical tissue supports the plant. The cover fabric protects against drying out and sunburn. The suction fabric ensures the flow of water from the soil. Conductive tissue distributes water and substances dissolved in it throughout the plant. Thus, these fabrics compensate for the disadvantages of the ground-air environment: low density, lack of water, high light intensity.
56. Why do you pinch the main root of some cultivated plants?
To stimulate the growth of adventitious and lateral roots developing in the upper, more fertile layer of soil.
57. What are plant and fungal spores?
Reproduction by spore formation is typical for algae, mosses, pteridophytes, and fungi. Spores are special cells, often covered with a dense membrane that protects them from adverse external influences. Typically, spores are produced in large quantities and have a negligible weight, which makes them easier to spread by wind and animals. Due to the small size of the spore, it contains only a minimal supply of nutrients. Due to the fact that many spores do not reach a place suitable for germination, their losses are very high. Under favorable environmental conditions, the spore shell opens, the cell divides repeatedly and gives rise to a new organism.
58. Read the text “Fertilization in Flowering Plants” and find sentences in it that contain biological errors. First write down the numbers of these sentences, and then formulate them correctly.
Response elements:
1) 2 - One of the cells of the pollen grain forms a long pollen tube through which male gametes – sperm – move
2) 4 - The embryo sac contains the egg and the central nucleus.
3) 5 - One of the sperm fuses with the egg, and the second sperm fuses with the central nucleus.
59. What consequences can result from adding excess mineral fertilizers to the soil?
To environmental pollution.
60. Why is the soil in forest plantations populated with mycorrhizal fungi?
Trees enter into symbiosis with fungi, which is why the plants take root well and more easily tolerate unfavorable conditions, especially drought, because plant roots receive additional nutrition.
61. What is the function of chlorophyll in a plant cell?
Absorbs energy sunlight and converts it into chemical bonds of organic substances.
62. For what purpose do you pinch off the tip of the root when transplanting cabbage seedlings?
When the division zone and growth zone of the main root are removed, cell division and growth are activated at the tips of the lateral roots. Due to the growth of lateral roots, the surface area for nutrient absorption increases.
Answer: To increase the number of lateral roots, which leads to an increase in the feeding area of plants.
63. Why is it necessary to loosen the soil when growing plants?
Answer: To improve root respiration and reduce water evaporation from the soil.
64. Mosses are representatives of the plant kingdom. The answer should reflect the role of plants in nature and the specific role of mosses related to their ability to accumulate water and form peat deposits.
Answer:
1) during photosynthesis they form organic substances and release oxygen into the atmosphere;
2) accumulate and retain water, causing waterlogging of the soil;
3) promote the formation of peat;
4) are producers in the ecosystem and a link in the food chain.
65. Experienced gardeners apply fertilizers to the soil along the edges of the trunk circles of fruit trees, rather than distributing them evenly. Explain why?
66. What basic rule must be observed when collecting mushrooms to maintain their numbers?
The mycelium should not be damaged, since new fruiting bodies will not grow on the destroyed mycelium.
67. How do substances move in multicellular algae without a conducting system?
Substances dissolved in water move from cell to cell through pores in the membrane and across the membrane by osmosis
1) Treatment of seeds before sowing with pesticides.
2) Application of crop rotation.
3) Sowing plant varieties resistant to smut fungi.
69. What are the structural features and vital functions of mushrooms?
1) Fungi are unicellular and multicellular organisms, the body of which consists of thin threads - hyphae.
3) Reproduction of mushrooms: spores, parts of mycelium - vegetative propagation; budding in yeast; sexual reproduction in some mushrooms
70.Why does plowing the soil improve the living conditions of cultivated plants?
Answer:
1) promotes the destruction of weeds and reduces competition with cultivated plants;
2) promotes the supply of plants with water and minerals;
3) increases the supply of oxygen to the roots.
71.What features are characteristic of mossy plants?
Answer:
2) mosses reproduce both sexually and asexually with alternating generations: sexual (gametophyte) and asexual (sporophyte);
3)mature plant moss is the sexual generation (gametophyte) and the capsule with spores is asexual (sporophyte);
4) fertilization occurs in the presence of water.
72.The process of photosynthesis occurs intensively in the leaves of plants. Does it occur in ripe and unripe fruits? Explain your answer.
Answer:
1) photosynthesis occurs in unripe fruits (while they are green), since they contain chloroplasts;
2) as they mature, chloroplasts turn into chromoplasts, in which photosynthesis does not occur.
73.Red algae (purple algae) live at great depths. Despite this, photosynthesis occurs in their cells. Explain why photosynthesis occurs if the water column absorbs rays from the red-orange part of the spectrum.
Answer:
1) photosynthesis requires rays not only from the red, but also from the blue part of the spectrum;
2) the cells of scarlet mushrooms contain a red pigment that absorbs rays from the blue part of the spectrum, their energy is used in the process of photosynthesis.
74.What is a fruit? What is its significance in the life of plants and animals?
Answer:
1) fruit - the generative organ of angiosperms;
2) contains seeds with the help of which plants reproduce and disperse;
3) plant fruits are food for animals.
75.Prove that the rhizome of the plant is a modified shoot.
Answer:
1) the rhizome has nodes in which rudimentary leaves and buds are located;
2) at the top of the rhizome there is an apical bud that determines the growth of the shoot;
3) adventitious roots extend from the rhizome;
4) internal anatomical structure rhizomes are similar to the stem.
76.Which part of the sheet is indicated in the figure by the letter A and what structures does it consist of? What functions do these structures perform?
1) the letter A denotes a vascular-fibrous bundle (vein), the bundle includes vessels, sieve tubes, and mechanical tissue;
2) vessels provide transport of water to the leaves;
3) sieve tubes provide transport of organic substances from leaves to other organs;
4) mechanical tissue cells provide strength and serve as the framework of the leaf.
77.What are the characteristic features of the fungal kingdom?
Answer:
1) the body of fungi consists of threads - hyphae, forming a mycelium;
2) reproduce sexually and asexually (spores, mycelium, budding);
3) grow throughout life;
4) in the cell: the membrane contains a chitin-like substance, a reserve nutrient - glycogen.
78. Experienced gardeners apply fertilizers into the grooves located along the edges of the trunk circles of fruit trees, rather than distributing them evenly. Explain why.
Answer:
1) the root system grows, the suction zone moves behind the root apex;
2) roots with a developed absorption zone - root hairs - are located at the edges of the trunk circles.
79.What modified shoot is shown in the figure? Name the structural elements indicated in the figure by numbers 1, 2, 3, and the functions that they perform. Sectional drawing of an onion.
Answer:
1) onion;
2)1 – a succulent scale-like leaf in which nutrients and water are stored;
3)2 – adventitious roots, ensuring the absorption of water and minerals;
4) 3– bud, ensures shoot growth.
80.What are the structural features and vital functions of mosses? Please provide at least three items.
Answer:
1) most mosses are leafy plants, some of them have rhizoids;
2) mosses have a poorly developed conducting system;
3) mosses reproduce both sexually and asexually, with alternating generations: sexual (gametophyte) and asexual (sporophyte); An adult moss plant is the sexual generation, and the spore capsule is asexual.
81. Why are mushrooms classified as a special kingdom of the organic world?
Answer:
1) the body of mushrooms consists of thin branching threads - hyphae, forming mycelium, or mycelium;
2) mycelial cells store carbohydrates in the form of glycogen;
3) mushrooms cannot be classified as plants, since their cells do not have chlorophyll and chloroplasts; the wall contains chitin;
4) mushrooms cannot be classified as animals, since they absorb nutrients over the entire surface of the body, and do not swallow them in the form of food lumps.
82. Name the main features of the structure and activity of bacteria. List at least four features.
Answer:
1) bacteria are prenuclear organisms that do not have a formed nucleus and many organelles;
2) according to the method of nutrition, bacteria are heterotrophs and autotrophs;
3) high rate of reproduction by division;
4) anaerobes and aerobes;
5) unfavorable conditions are experienced in a state of dispute.
83.What are the structural features and vital functions of mushrooms? Please indicate at least three characteristics.
Answer:
1) fungi - unicellular and multicellular organisms, the body of which consists of thin threads - hyphae;
3) reproduction of mushrooms: spores, parts of mycelium - vegetative propagation; budding in yeast; sexual reproduction of some fungi.
84. How is the complexity of ferns compared to mosses? Give at least three signs.
Answer:
1) the ferns have roots;
2) ferns, unlike mosses, have developed developed conductive tissue;
3) in the development cycle of ferns, the asexual generation (sporophyte) predominates over the sexual generation (gametophyte), which is represented by the prothallus.
85.What characteristics do plants living in arid conditions have?
Answer:
1) the root system of plants penetrates deeply into the soil, reaches groundwater or is located in the surface layer of soil;
2) in some plants, water is stored in leaves, stems and other organs during drought;
3) the leaves are covered with a waxy coating, pubescent or modified into spines or needles.
86.Name at least three aromorphoses in land plants that allowed them to be the first to develop land. Justify your answer.
Answer:
1) the appearance of integumentary tissue - the epidermis with stomata - facilitating protection against evaporation;
2) the emergence of a conducting system that ensures the transport of substances;
3) development of mechanical tissue that performs a supporting function.
87.What are the features of the structure and life activity cap mushrooms? Name at least four features.
Answer:
1) have a mycelium and a fruiting body;
2) reproduce by spores and mycelium;
3) according to the method of nutrition - heterotrophs;
4) most form mycorrhizae.
88.In what ways does the kingdom of fungi differ from the kingdom of plants? Name at least three signs.
Answer:
1) mushrooms are heterotrophs, not capable of photosynthesis;
2) mushrooms differ in structure and chemical composition cells: do not have chloroplasts, the cell wall contains chitin, the reserve nutrient is glycogen;
3) the body of fungi is formed by hyphae.
89. Can seeds sprout in a garden bed with their roots up and shoots down if they were sown at random?
1. No
2. The root grows vertically downwards (geotropism), and the shoot grows upwards (phototropism).
90. Why are large seeds selected for sowing?
1. Large seeds have more nutrients.
2. Large seeds produce stronger seedlings.
91. Why does plowing the soil improve the living conditions of cultivated plants?
1. Promotes the destruction of weeds and reduces competition with cultivated plants.
2. Helps supply plants with water and minerals.
3. Increases oxygen supply to roots.
92. What fertilizers and why do you need to add to the soil to get a large head of cabbage?
1. Nitrogen (urea, potassium nitrate, ammonium sulfate)
2. Because they enhance the growth of stems and leaves.
93. What fertilizers and why do you need to add to the soil to get large potato tubers?
1. potassium fertilizers (potassium chloride, potassium nitrate)
2. because they enhance the growth of roots, bulbs and tubers
94. What fertilizers and why do you need to add to the soil to get large tomato fruits?
1. Phosphorus fertilizers (superphosphate, bone meal)
2. because they accelerate the growth and ripening of fruits.
95. How do the embryos of dicotyledonous and monocotyledonous plants differ?
1. In dicotyledons, the embryo usually has 2 cotyledons, in monocotyledons
2. In two-year-olds the embryo is symmetrical, and in one-year-old embryo it is asymmetrical.
3. In dicots, cotyledons usually germinate aboveground, in monocotyledons - usually underground.
96. What tissue of flowering plants connects its organs into a single whole?
Conductive tissue (wood vessels and bast sieve tubes)
97. How do plants differ from animals? Name at least three signs.
1) plants lead an attached lifestyle and grow throughout their lives;
2) plant cells contain plastids, chlorophyll, a cell wall made of cellulose, vacuoles with cell sap;
3) plants are autotrophs, producers capable of creating organic substances from inorganic ones using solar energy and releasing oxygen.
98. What features are characteristic of the plant kingdom?
1) the presence in cells of chloroplasts in which photosynthesis occurs
2) the presence in the cells of a cell membrane and vacuoles with cell sap
3) grow throughout life, most do not move from one place to another
99. What are the structural features and vital functions of mosses?
1) most mosses are leafy plants, some of them have rhizoids
2) mosses have a poorly developed conducting system" ;"
3) mosses reproduce both sexually and asexually, with alternating generations: sexual (gametophyte) and asexual (sporophyte); an adult moss plant is a sexual generation, and a capsule with spores is asexual
100. What features are characteristic of conifers?
1.propagation by seeds that lie open on the scales of cones
2.fertilization does not require an aqueous environment
3.leaves are scaly or needle-shaped, covered with a waxy coating
101. What features are characteristic of angiosperms?
1.availability of flower
2.presence of fruits with seeds
3.double fertilization
4. diversity of ecological forms and groups
102. What processes ensure the movement of water and minerals throughout the plant? Explain your answer.
1) from the root to the leaves, water and minerals move through the vessels due to transpiration, which results in suction force;
2) the upward flow in the plant is facilitated by root pressure, which arises as a result of the constant flow of water into the root due to the difference in the concentration of substances in the cells and the environment.
103. What process in the life of a tree is disrupted when its bark is removed?
Without the bark and sieve tubes in it, the plant will not be able to conduct organic substances to the cells of the roots and other organs and will soon die.
104. Growth rings are visible on the cut of a tree. Explain why they are different widths.
The width of the annual ring depends on the environmental conditions that have changed in different years tree life; under favorable conditions, the width of the ring is greater, since the cambium is divided more intensively.
106. Prove that the rhizome of a plant is a modified shoot.
1. The rhizome has nodes in which rudimentary leaves and buds are located; apical bud determines shoot growth.
2. Adventitious roots extend from the rhizome; The internal anatomical structure of the rhizome is similar to the stem.
107. Determine which part of the onion bulb is indicated in the figure by the letter B, explain its structure and functions.
1) modified sheet;
2) structure: juicy white scales, devoid of chlorophyll, have a thin skin;
3) functions: a supply of water with nutrients dissolved in it.
108. What functions, besides aerial nutrition, do the leaves of a plant perform?
Sheet functions:
1. Respiration (gas exchange) - absorption of oxygen and release of carbon dioxide occurs through the stomata of the leaf.
2. Transpiration - evaporation of water by leaves. Excess water in the form of water vapor is evaporated by the leaves through the stomata. Evaporation of water protects plants from overheating.
3. The leaf protects plants from slagging, in the form of autumn leaf fall. Together with fallen leaves, the plant is freed from unnecessary and harmful substances.
4. The leaf is an organ of vegetative reproduction.
109. What role do stomata play in the life of a plant?
110. Predatory plants, for example, sundews, feed on small insects. Explain what this way of eating is connected with?
This is explained by the fact that the sundew plant grows in a swamp, and the soil in the swamp is very poor in humus, so the plant receives few mineral salts, including those containing nitrogen. Nitrogen salts are needed for the formation of proteins in the body. Sundew, “digesting” animal proteins, thus overcomes protein hunger. Such nutrition is associated with the habitat and arose as an adaptation to environmental conditions.
111. How can you explain that multicellular plants consist of several types of tissues?
With the advent of multicellularity, different functions appeared in plant organs, and these functions could only be performed by special formations - tissues. It is necessary to conduct substances to organs located far from each other; this is done by conductive tissues. Excess substances accumulate in the cells of the main tissue, etc.
112. Why did angiosperms occupy a dominant position on Earth?
1. The life forms of angiosperms are represented by trees, shrubs, and herbs, which determines their greatest ecological plasticity.
2. Vegetative organs (roots, leaves, shoots) have numerous modifications and are the most specialized in structure and function.
3. Angiosperm seeds are protected by the pericarp, which contributes to their better preservation and distribution.
4. Fertilization does not require water, and pollination methods are very diverse (insects, wind, self-pollination, etc.).
5. They are spread by wind, water, animals or humans.
113. Why do many seeds not germinate when there is excess water in the soil?
114. The seeds of Siberian pine are called pine nuts. Explain. Is this name fair from a scientific point of view?
1) nut - the fruit of angiosperms;
115. Why is there life without plants? modern form on Earth would be impossible?
1) plants, through the process of photosynthesis, form organic substances - food for other organisms;
2) they maintain the constancy of the gas composition of the atmosphere, releasing oxygen in the light and absorbing carbon dioxide.
116. How is the complexity of ferns compared to mosses? Give at least 3 signs.
117. Red algae live at great depths. Despite this, photosynthesis occurs in their cells. Explain how photosynthesis occurs. If the water column absorbs rays from the red-orange part of the spectrum.
1) photosynthesis requires rays of the red and blue parts of the spectrum;
2) the cells of scarlet mushrooms contain a red pigment that absorbs rays from the blue part of the spectrum, their energy is used in the process of photosynthesis.
118. Name the fruits indicated letters A, B, and the plants for which they are characteristic. What do their fruits have in common? How are they different?
1) A-kernel (wheat). B - achene (sunflower);
2) general: dry single-seeded fruits;
3) differences: in the caryopsis the seed coat is fused with the pericarp, the fruit is indehiscent, the achene is a dehiscent fruit.
119. Which kidney is shown in the picture? What elements of its structure are indicated by numbers 1 and 2? What tissue is responsible for the development of the kidney?
1) flower (generative) bud;
2) 1 - rudimentary stem, 2 - rudimentary flower (inflorescence);
3) the growth and development of the kidney occurs due to the educational tissue in the growth cone
120. How do plants of the dicotyledonous class differ from plants of the monocotyledonous class? Give at least 4 signs.
1) in dicotyledons there are two cotyledons in the seed embryo, in monocotyledons there is one;
2) the root system of dicotyledons is usually taprooted, and that of monocotyledons is fibrous;
3) in dicotyledons the leaves are simple and complex, the venation is reticulate, in monocotyledons the leaves are always simple, the venation is parallel and arcuate;
4) as a rule, dicotyledons have flowers with a double perianth, four- or five-membered, while monocots have flowers with a simple perianth, three-membered.
121. What functions do they perform? different zones young root?
1. In the division zone, the number of young cells increases, the root grows in length;
2. In the growth zone, cells increase in size and their differentiation occurs;
3. In the suction zone, root hairs absorb water from the soil with minerals dissolved in it;
4. In the movement zone, the movement of substances takes place.
122. How is the work of stomata regulated?
1. The gap is located in the epidermis, surrounded by two guard cells and serves for transpiration and gas exchange.
2. guard cells are involved in photosynthesis and accumulation of organic substances;
3. When carbohydrates accumulate, water enters the guard cells. Turgor pressure increases, the stomatal fissure opens in the absence of photosynthesis, the guard cells collapse, and the fissure closes.
123. How does a pine seed differ from a fern spore? Their similarities.
1. A seed, unlike a unicellular spore, is a multicellular formation, consisting of an embryo and accumulated substances
2. The spore has a haploid set of chromosomes and gives rise to a gametophyte. The seed embryo is diploid and gives rise to a sporophyte, an adult plant.
3. the seed, like a spore, ensures the reproduction and spread of plants
124. Explain why water rises up tree trunks tens of meters, for example, up to 100 m in eucalyptus. Answer:
1) under the influence of root pressure;
2) due to the evaporation of water from the surface of the leaves.
125. All plants are conventionally divided into lower and higher. Along with similarities, there are also differences between them. What is the main one?
The body of lower plants (thallus, thallus) lacks tissues and organs.
126. Bryophytes are one of the oldest groups plants. From whom did they come in the process of evolution? How can this be proven?
Bryophytes evolved from algae. This is confirmed by the great similarity of the protonema (pre-growth) of mosses with filamentous green algae.
127. Second in number after angiosperm department higher plants are bryophytes. They are widespread throughout to the globe. What is their main meaning in nature?
1) Causes waterlogging of the area.
2) Participate in the formation of peat.
3) Can participate in soil formation.
128. One of the prerequisites for plants to successfully reach land was their acquisition of tissues specialized in carrying various substances throughout the body. In the process of evolution, the significance of these tissues has expanded. List the functions that conducting tissues can perform in modern vascular plants?
1) Conduct nutrients.
2) Serve as the main support for plants
3) Participate in the storage of nutrients.
129. It is known that in agricultural practice, before sowing seeds, they are checked for germination. Explain how and why they do this.
1) to determine the germination of seeds, a certain number of them (100) are placed in optimal conditions for germination and the percentage of germinated seeds is calculated;
2) germination is determined to establish the quality of the seed, on which the plant’s yield depends.
130. Why are mosses classified as higher spore plants?
1. cell differentiation occurred, tissues appeared
2. the body is divided into organs: stem and leaves
3. reproduce by spores
131. In what forms do movements appear in plants? Answer:
1. bends of plants towards the light - phototropism
2. movement of the stem up and the root down under the influence of gravity - geotropism
3.plant movement influenced chemicals or mechanical influences - chemotropism.
132. Woody plants growing in areas with a constant wind direction have a flag-shaped crown. Plants grown from cuttings of these trees under normal conditions have a normal crown shape. Explain these phenomena.
1) the flag-shaped crown is formed under the influence of external conditions (wind) and is explained by modification variability;
2) during vegetative propagation using cuttings, the genotype does not change; in the absence of wind, a normal crown is formed.
133. What type of sheet is shown in the picture? Which parts of the sheet are indicated in the figure by numbers 1 and 2 and what functions do they perform?
1) a simple leaf with reticulate veins and stipules;
2) 1 - leaf blade, performs the functions of photosynthesis, gas exchange, transpiration, and in some plants - vegetative propagation;
3) 2-veins provide transport of substances and leaf support.
134. Name the parts of the flower indicated on the diagram by numbers 1, 2, 3, and explain their functions.
1) 1- stamens - the organ of sexual reproduction, form pollen involved in pollination;
2) 2 - pistil ovary, participates in sexual reproduction, contains an ovule with an egg (female gamete);
3) 3 - sepals and petals of the corolla (perianth), serve to protect the stamens and pistil, and participate in attracting insects (pollination).
135. Name the parts of the woody stem indicated in the figure by numbers 1, 2, 3, and indicate the functions that they perform.
1) 1- cork (covering tissue), performs a protective function;
2) 2 - bast (bast fibers and sieve tubes), performs a mechanical function and conduction of organic substances;
3) 3 - cambium (educational tissue), ensures the growth of the tree in thickness.
136. Name the vegetative organ of the plant shown in the figure, its structures indicated by numbers 1 and 2, and the functions they perform. What role does this vegetative organ play in the life of a plant?
1) bulb - a shortened modified shoot, participates in vegetative propagation, accumulates nutrients;
2) 1 - bottom, a modified stem from which adventitious roots grow and buds form on it;
3) 2 - dry scaly leaf; protects the bulb from drying out and damage.
137. By what characteristics are plants of the Liliaceae and Cereals families classified as Monocots? Please indicate at least 4 characteristics.
1) seed with one cotyledon;
2) fibrous root system;
3) simple leaves with parallel or arcuate veins;
4) a three-membered flower with a simple perianth.
138. What parts of the bean seed embryo are indicated in the figure by numbers 1 and 2, what functions do they perform?
1) 1 - root, bud (embryo-stem and leaves), 2 - cotyledons;
2) the root develops into the main root, a shoot develops from the bud;
3) cotyledons - provide the seedling with nutrients.
139. In small rooms with abundance indoor plants At night, oxygen concentration decreases. Explain why.
1) at night, with the cessation of photosynthesis, the release of oxygen stops;
2) in the process of plant respiration (they breathe constantly), the concentration of oxygen decreases and the concentration of carbon dioxide increases.
140. The corn plant has two types of inflorescences: the cob and the panicle. Why do fruits form only on the cob and sometimes part of the cob is not filled with grains?
1) the spadix consists of female flowers, in which fruits are formed - caryopses, the panicle consists of male flowers;
2) not all flowers of the spadix are pollinated and fertilized, so part of the spadix will be empty.
141. It is known that it is difficult to experimentally detect the respiration of plants in the light. Explain why.
1) in the light in the plant, along with respiration, photosynthesis occurs, in which carbon dioxide is used;
2) as a result of photosynthesis, much more oxygen is produced than is used during plant respiration.
142. Identify the root zones indicated in the figure by numbers 1,2,4, and indicate their functions.
Response elements:
1) 1- root cap, protects the root tip from mechanical damage;
2) 2 - division zone, ensures root growth in length due to cell division;
3) 4 - suction zone, the zone of root hairs, ensures the absorption of water and minerals.
143. Why does the root stop growing in length after removing its tip? What is the purpose of this technique when transplanting plants?
1) at the apex of the root there is educational tissue, the removal of which leads to the cessation of root growth in length
2) removal of the root tip promotes the formation of lateral roots, which increase the plant’s feeding area.
144. Plants absorb a significant amount of waste during their life. Which two main life processes use the majority of water consumed? Explain your answer. Elements of the answer:
1) evaporation, which ensures the movement of water and dissolved substances and protection from overheating;
2) photosynthesis, during which organic substances are formed and oxygen is released.
145. Why are potato tubers not classified as fruits? Explain your answer. Provide at least 3 pieces of evidence. Response elements:
1) tubers do not have seeds;
2) their formation and development are not related to the structures of the flower;
3) the structure of the tuber corresponds to a modified shoot
146. How is a pine seed different from a fern spore and what are their similarities?
1) a seed, in contrast to a unicellular spore, is a multicellular formation consisting of an embryo and a supply of nutrients;
2) the spore has a haploid set of chromosomes and gives rise to a gametophyte (prothallus), and the seed embryo is diploid and gives rise to a sporophyte (adult plant);
3) the seed, like the spore, ensures the reproduction and dispersal of plants.
147. Explain why to grow leguminous plants no fertilizing with nitrogen fertilizers is required.
1) nodule bacteria settle on the roots of legumes;
2) they absorb nitrogen from the air and provide plants with nitrogen nutrition.
148. Which part of the sheet is indicated in the figure by the letter A and what structures does it consist of? What functions do these structures perform?
1) the letter A denotes a vascular-fibrous bundle: (vein), the bundle includes vessels, sieve tubes, mechanical tissue;
2) vessels provide transport of water to the leaves;
3) sieve tubes provide transport of organic substances from leaves to other organs;
4) the cells of the mechanical tissue give strength and are the frame of the sheet.
149. Describe the features of the Plant kingdom. Give at least four signs.
1) the presence in cells of chloroplasts in which photosynthesis occurs;
2) the presence in the cell of a durable fiber shell, which gives it shape;
3) the presence of vacuoles filled with cell sap;
4) growth throughout life, practically do not move from one place to another;
5) absorption of nutrients by the body surface.
150. How is the complexity of ferns compared to mosses manifested? Give at least three signs.
1) the ferns have roots;
2) in ferns, unlike mosses, developed conductive tissue has formed;
3) in the development cycle of ferns, the asexual generation (sporophyte) predominates over the sexual generation (gametophyte), which is represented by the prothallus.
151. Why is a tuber considered a modified underground shoot? Provide at least three pieces of evidence.
1) in the light, chloroplasts are formed, in which photosynthesis occurs;
2) buds (eyes) are located on the tuber;
3) there are nodes and internodes like a shoot.
152. By what signs can you distinguish a modified shoot from a modified root?
1) The modified root does not have buds
2) Modified roots do not have scales - modified leaves.
153. A researcher took two groups of cells and placed them in different test tubes with a nutrient medium. He removed the nucleus from one group of cells. Another group of cells remained unharmed. How will the number of cells in different groups change after some time and why?
1) The nucleus is responsible for cell division.
2) Without a nucleus, cells do not divide and die after a while.
154. How can we explain that multicellular plants consist of several types of tissues?
1) the need to absorb and deliver nutrients to different distances in connection with reaching land.
2) in connection with the performance of various functions by plant organs.
155. What developmental features helped plants conquer land?
1) The appearance of organs that perform certain functions.
2) the appearance of specialized tissues.
3) The emergence of a flower and a seed.
4) Reducing the dependence of the organism’s reproduction on water.
156. The process of photosynthesis occurs intensively in the leaves of plants. Does it occur in ripe and unripe fruits?
1) photosynthesis occurs in unripe fruits (while they are green), since they contain chloroplasts;
2) as they mature, chloroplasts turn into chromoplasts, in which photosynthesis does not occur.
157. It is known that in sphagnum bogs, despite the large amount of moisture, water is inaccessible to many plants. What is this connected with?
1) roots, like other plant organs, carry out the respiration process and need oxygen; in sphagnum bogs, due to poor aeration, it is not enough;
2) the growth of roots is also hampered by acidification of the water and soil of the swamps;
3) and toxic substances accumulate in the water and soil of sphagnum bogs that interfere with the development of plants.
158. Why do many seeds not germinate when there is excess water in the soil?
When there is an excess of water in the soil, there is a lack of oxygen, which is necessary for plant respiration. The germinating seeds of most plants receive a significant portion of their oxygen from the free spaces of the soil, and not from water.
159. It is known that before transplanting young plants into the ground, they are picked (the tip of the main root is pinched off). Why do they do this?
1) when picking plants, the growth of adventitious and lateral roots is activated;
2) due to the increase in the total number of adventitious and lateral roots, the mineral nutrition of the plant improves, which stimulates its growth.
160. When potatoes were introduced into culture, potato riots arose in Russia. Why didn't the peasants want to grow this plant?
1) the peasants did not know that they needed to eat tubers and ate green berries;
2) potato berries are poisonous and cause severe poisoning.
161. Gardeners, when picking cabbage seedlings, pinch the top of the main root, and when propagating currant bushes, they use stem cuttings on which adventitious roots develop. Both of these flowering plants belong to the class of dicotyledons. Explain what type of root system will be in cabbage grown from this seedling, and what type of root system will be in currants grown from a stem cutting.
1) The type of root system is initially taproot in cabbage and currants (dicots).
2) When picking cabbage, after pinching, the main root stops growing in length (since the zones of division and growth are removed) and the development of lateral and adventitious roots begins. When currant stem cuttings root, adventitious roots develop. Thus, the root system in both cases will become similar to the fibrous one (predominant development of lateral and adventitious roots).
162. The flowers of many angiosperms are pollinated by insects. Explain the mutual benefits of cross-pollination for insects and plants.
1) For plants: thanks to insects, the probability of pollination increases, the possibility of offspring acquiring new characteristics (variability and better fitness) increases.
2) For insects: plants are a source of food (pollen and nectar), a refuge.
163. Why does plowing the soil improve the living conditions of cultivated plants?
1) promotes the destruction of weeds and reduces competition with cultivated plants;
2) contributes to the supply of plants with water and minerals;
3) increases the supply of oxygen to the roots.
164. In the 17th century, the Dutch scientist Van Helmont conducted an experiment. He planted a small willow tree in a tub of soil, after weighing the plant and soil, and only watered it for several years. After 5 years, the scientist weighed the plant again. Its weight increased by 63.7 kg, the weight of the soil decreased by only 0.06 kg. Explain why the increase in plant mass occurred, what substances from the external environment ensured this increase.
1) the mass of the plant has increased due to organic substances formed during photosynthesis;
2) in the process of photosynthesis, water and carbon dioxide are used, which come from the external environment.
165. What is the importance of leaf fall for plants in mid-latitudes?
1) Leaf fall is an adaptation of plants to reduce water evaporation in autumn and winter.
2) It also reduces the likelihood of branches breaking off under the weight of snow.
3) In addition, this removes harmful substances accumulated over the summer from the plant.
166. Name the adaptations of plants to life in dry conditions.
1) the root system of plants penetrates deeply into the soil, reaches groundwater or is located in the surface layer of soil;
2) in some plants, water is stored in leaves, stems and other organs during drought;
3) the leaves are covered with a waxy coating, pubescent or modified into spines or needles.
167. What is the significance in the life of plants of beekeepers placing hives in buckwheat fields?
Bees feed on buckwheat pollen and nectar and carry out cross-pollination, which increases plant productivity.
168. If the weather is cold and rainy when the apple trees are flowering, the apple harvest decreases. Explain your reasons.
1) the apple tree is an insect-pollinated plant, and in cold rainy weather insects do not fly,
2) pollination, fertilization and fruit formation do not occur.
169. Why does potato yield increase after hilling?
Hilling stimulates the formation of adventitious roots, which means it increases the mass of the root system. As a result, root nutrition improves and potato yields increase.
170. Why is it necessary to loosen the soil when growing plants?
Loose soil contains more oxygen, which is necessary for plants to breathe. In addition, when loosening, soil capillaries are broken, through which water easily rises to the surface and then evaporates. In this way, moisture is retained in the soil (which is why loosening is often called dry watering).
171. Experienced gardeners apply fertilizers to the soil along the edges of the trunk circles of fruit trees, rather than distributing them evenly. Explain why?
The root system grows, the suction zone moves behind the root apex. Roots with a developed absorption zone - root hairs - are located at the edges of the trunk circles.
172. How, using a magnet, can you clean the seeds of cultivated plants (for example, flax, clover, alfalfa) from weed seeds?
1) weeds have fuzzy seeds that cling to animal fur
2) the clogged seeds are sprinkled with iron powder (grains of iron stick around the weed seeds), and then using a magnet they are separated into clean seeds and weed impurities
173. What is the importance of photosynthesis for life on Earth?
The importance of the process of photosynthesis for life on Earth is as follows: photosynthesis provides all living organisms with the organic substances they need. During photosynthesis, light energy is converted into chemical energy available to living organisms. During the light phase of photosynthesis, a by-product is released - molecular oxygen, which is necessary for respiration for most organisms.
174. What processes ensure the movement of water and minerals throughout the plant? Explain your answer.
1) from the root to the leaves, water and mineral salts dissolved in it move through the vessels due to transpiration, as a result of which suction force arises;
2) the upward flow of the plant is facilitated by root pressure, which arises as a result of the constant flow of water into the root due to the difference in the concentration of substances in the cells and the environment.
175. Explain through what tissues and how substances are transported in angiosperms.
1) the movement of water and minerals is carried out through the vessels of wood;
2) the movement of organic substances occurs through the sieve tubes of the phloem;
3) water and minerals move from the roots along the stem to the leaves as a result of root pressure and the suction force that occurs when water evaporates;
4) organic substances move from photosynthetic cells due to differences in concentration and pressure.
176. Find errors in the given text, correct them, indicate the numbers of the sentences in which they are made, write down these sentences without errors.
1. Plants, like all organisms, undergo metabolism.
2.They breathe, eat, grow and reproduce.
3.When they breathe, they absorb carbon dioxide and release oxygen.
4.They grow only in the first years of life.
5. All plants are autotrophic organisms by type of nutrition; they reproduce and spread using seeds.
Response elements:
1)3- when breathing, plants absorb oxygen and release carbon dioxide;
2) 4 - plants grow throughout their lives;
3) 5 - not all plants form seeds
177. What is called double fertilization?
In flowering plants, in addition to the fusion of haploid gametes - one of the sperm with the egg and the formation of a diploid zygote, from which the seed embryo develops, the second sperm merges with a diploid secondary cell and the formation of triploid cells, from which the endosperm is formed.
178. In what processes of plant life does water participate?
Water is involved in root nutrition, the movement of substances within the plant, photosynthesis and evaporation, cooling the surface of the leaves and protecting them from burns.
179. Read the text “Fertilization in Flowering Plants” and find sentences in it that contain biological errors. First write down the numbers of these sentences, and then formulate them correctly.
1. The pollen grain, once on the stigma of the pistil, germinates. 2. One of the cells of the pollen grain forms a long pollen tube, along which female gametes - eggs - move. 3. Lengthening, the tube passes between the cells of the stigma and style and reaches the ovule. 4. The embryo sac contains two mature sperm. 5. One of the sperm merges with the egg, and the second dies. 6. The fusion of female and male gametes is called fertilization.
1)2 - One of the cells of the pollen grain forms a long pollen tube along which male gametes – sperm – move
2)4 - The embryo sac contains the egg and the central nucleus.
3)5 - One of the sperm fuses with the egg, and the second sperm fuses with the central nucleus.
180. What role do stomata play in plant life?
Stomata is a highly specialized formation of the plant epidermis, consisting of two guard cells and an intercellular space (stomatal fissure) between them. Transpiration and gas exchange occur through the stomata. Transpiration is the evaporation of water by a plant. Transpiration regulates the water and temperature regime of the plant.
181. What is the difference between root vegetables and root tubers?
The root crop is formed from the main root and the lower part of the stem, root tubers - from the lateral and adventitious roots.
182. Prove that the lily of the valley rhizome is a modified shoot.
1) the rhizome has nodes in which rudimentary leaves and buds are located;
2) at the top of the rhizome there is an apical bud that determines the growth of the shoot;
3) adventitious roots extend from the rhizome;
4) the internal anatomical structure of the rhizome is similar to the stem.
183. What biological features of cabbage should be taken into account when growing it?
ANSWER: Its cold resistance, moisture-loving, light-loving, soil nutritional requirements and the fact that it is a biennial plant.
184. Why on forest paths Are there any plants missing or very sparse?
ANSWER: Constant trampling leads to compaction of the soil, disruption of the water and air regime of the roots, and oppression of plants.
185. Why do apples of many varieties become loose when stored for a long time?
ANSWER: During long-term storage, the intercellular substance is destroyed.
186. In the swampy areas of the tundra, many plants suffer from a lack of moisture. What is this connected with?
ANSWER: Cold water is poorly absorbed by the roots.
187. How are plants adapted to life in the tundra?
1. In the tundra in summer there is a lot of light, but a lack of temperature, and therefore the soil thaws to a shallow depth, under which there is permafrost.
2. the roots cannot go into the soil, which means there are no tall plants in the tundra; the vegetation cover is represented by lichens, mosses, herbaceous plants
3. trees such as dwarf birch and willow are represented by dwarf forms
4. in the tundra - short growing season, small leaves
188. Why, when potato tubers are stored for storage, their weight decreases by spring?
ANSWER: During storage, living cells respire and during respiration they use organic substances and evaporate water
189. Why do potato tubers become crumbly when cooked for a long time?
ANSWER: During cooking, the intercellular substance that binds cells is destroyed.
190. Why do frozen apples release sweet juice when they thaw?
ANSWER: When frozen, cells are destroyed, and when thawed, cell sap flows out of the vacuoles.
191. Why does the cut surface become wet when cutting an apple?
ANSWER: When cut, the vacuoles are damaged and cell sap leaks out of them.
192. What features of psilophytes allowed them to be the first to develop land? Justify your answer.
ANSWER: The appearance of integumentary tissue - epidermis with stomata to protect against evaporation. The emergence of an underdeveloped conducting system for the transport of substances. The appearance of mechanical tissue to perform a supporting function. The presence of rhizoids for fixation in the soil.
193. What are the similarities and differences between the fruits of plants from the families of the Mothaceae (Bean) and Cruciferous (Cabbage) families?
ANSWER: Butterraceae have a bean fruit, while Cruciferae have a pod or pod. Similarities: bean and pod (pod) are dry multi-seeded dehiscent fruits. Differences: the seeds inside the bean lie on the valves, and in the pod - on a membranous partition.
194. What are the similarities and differences between the fruits of plants of the Poaceae and Asteraceae families?
ANSWER: Similarities: they have single-seeded, indehiscent fruits. Differences: in cereals the fruit is a caryopsis, and in Asteraceae the fruit is an achene. In the caryopsis, the seed coat fuses with the pericarp, and in the achene, the seed lies freely; the fruits may have tufts, parachutes, and trailers.
195. The student indicated in his answer that plants of the Moth family (Legumonaceae) have a regular five-membered flower, a fibrous root system and a fruit pod. Find errors in this answer and comment them.
ANSWER: The Moth flower is five-membered, irregular: an unpaired petal is a sail, paired petals are oars and fused petals are a boat. The root system is taprooted, as this family belongs to the Dicotyledonous class. The fruit is a bean, not a pod.
196. Explain why when sowing small seeds at great depths, seedlings do not develop?
ANSWER: Small seeds contain few nutrients, which are not enough for the seedling to reach the soil surface.
197. What features of the fruit - the drupe - ensure the dissemination of seeds of many representatives of plants of the Rosaceae family?
ANSWER: A drupe is a one-seeded fruit with brightly colored juicy pulp, which attracts animals. Drupes are eaten by birds and mammals, while the seeds, covered with the woody part of the pericarp, are not digested in the digestive canal and are removed with droppings.
198. What is the significance of various flowers in the inflorescences of plants of the Asteraceae family?
ANSWER: tubular and reed-shaped - for the formation of seeds (located in the center), funnel-shaped and false-lingual - to attract pollinating insects (located at the edges).
199. Name at least 3 features of land plants that allowed them to be the first to develop land. Justify your answer.
ANSWER: 1) the appearance of integumentary tissue - epidermis with stomata, which helps protect against evaporation; 2) the appearance of a poorly developed conducting system that ensures the transport of substances; 3) development of mechanical tissue that performs a supporting function; 4) the formation of rhizoids, with the help of which they were fixed in the soil.
200. What connection exists between water evaporation and the movement of minerals in a plant?
1) As a result of evaporation of water by leaves, its content in plant cells decreases, and the concentration of cell sap increases, and the osmotic pressure increases;
2) Due to osmotic pressure, water with salts dissolved in it flows from the root and stem into the leaves.
1) In a saline solution, cells lose water, plasmolysis occurs;
2) Cells shrink, turgor drops, and the plant withers.
201. What are the structure and functions of seeds in flowering plants?
1) Structure: peel, embryo, endosperm (sometimes underdeveloped)
2) Seeds ensure plant reproduction
3) Provide relocation and endurance of unfavorable conditions
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Gymnosperms - very ancient plants. Remains of their fossils are found in layers Devonian period Paleozoic era. Currently, gymnosperms are mainly trees (up to 100 m in height), shrubs, tree-like vines and even epiphytes. Herbs are represented by only one reliably known species - Williamsoniella (from the Bennitaceae).
Coulter's pine Ginkgo biloba Cycad averted
Branching of gymnosperms is mainly monopodial ; wood consists almost entirely of tracheid , there are no vessels (with the exception of pressure vessels). Most gymnosperms have needle-shaped (needles) or scale-like leaves; a few have large, often dissected leaves, similar to fronds of ferns or palm leaves. These are predominantly evergreen, mono-, di- or polyecious plants. The roots (main and lateral) have the usual structure for trees and shrubs, with mycorrhiza. Adventitious roots are very rare (among primitive representatives).
A distinctive feature of all gymnosperms is the presence ovules (ovules) and seed formation. The ovules are located openly on megasporophylls or at the ends of stems, which is why the plants are called gymnosperms. Openly lying seeds develop from the ovule. The ovule is a megasporangium surrounded by an integument. Seeds always contain nutritious tissue - endosperm; during germination, the cotyledons are brought to the surface and perform the functions of leaves.
Seed ferns- completely extinct plants that existed from the late Devonian to the early Cretaceous. These were tree-like plants or vines that had large leaves, similar to fronds of ferns, and adventitious roots. In addition to assimilating leaves, they had spore-bearing leaves; some had microsporangia and megasporangia with ovules. Seed ferns are a transitional group from ferns to seed plants. Apparently, other seed plants originated from them. The remains of seed ferns play a large role in the formation of coal in the territories of Russia, Western Europe and North America.
Heyday of conifers falls on Jurassic period. This is the largest and most widespread group among modern gymnosperms. Conifers are evergreen plants, with the exception of larch and metasequoia. They are represented mainly by trees with a height of 10-15 to 100 m, tree-like stylates, and shrubs with monopodial branching. Needle-shaped (needles) or cone-shaped leaves are located on the stem in a spiral (single) or collected in bunches, scale-shaped leaves are opposite.
Conifers have a powerfully developed secondary xylem (wood), consisting of 90-95% tracheids. The bark and pith are poorly developed. The embryonic primary root usually turns into a powerful tap root and functions throughout life. Two forms of roots often develop: usually elongated and highly branched and shortened. It is the latter that are essentially mycorrhiza. Root hairs are localized in a narrow zone. Many conifers have resin passages in their bark, wood and leaves containing essential oil, resins, balms.
Conifers are monoecious plants, less often dioecious. For example, pine is a monoecious plant, male and female bumps are formed on one plant. Typically, it reaches a height of 50 m and lives up to 400 years. Sporulation occurs in the 30-40th year of life, but it can happen earlier.
Sporophylls are collected in cones of two types, which differ sharply from each other: men's represented by paniculate “inflorescences”, women's - single. A male cone, having an ellipsoidal shape, 4-5 cm long, 3-4 cm in diameter, is formed in the axil of the scales at the site of a shortened shoot and is a shoot with a well-developed axis (rod), on which there are spirally locatedmicrosporophylls- reduced spore-bearing leaves. They can be considered as homologs of angiosperm stamens. Microsporangia (anthers) are formed on the microsporophylls on the lower side.
Female cones are formed at the tops of young shoots; they are larger in size and more complex in structure. On the main axis, in the axils of the covering scales, thick scales with two ovules on the upper side are formed. These scales are called seed scales. A female cone is a group of metamorphosed shortened side shoots located on a common axis.
Inside is a microsporangium on a male cone ( A ) by autumn a large number of mother cells are formed microspores . In the spring, they divide reductionally and form haploid microspores (four haploid microspores are formed from each diploid mother cell). Microspore ( IN ) is dressed in two shells and carries two air bags. Germination of microspores occurs in microsporangium with the subsequent development of a reduced gametophyte: the microspore nucleus divides mitotically (twice: the first two cells disappear and two nuclei are formed again) to form an antheridial cell, in which male gamete cells are formed - sperm , and vegetative, with the help of which male gametes are delivered to the egg; pollen tube develops G ) due to the enzymatic growth of the vegetative cell. In gymnosperms, the organ of sexual reproduction, the antheridium, has already disappeared. The microspore covers remain the pollen covers. After the pollen ripens, the microsporangia open and the pollen spills out. Air sacs facilitate the transfer of pollen by wind. Further development of the male gametophyte occurs after pollination on the female cones inside the ovule.
Young ovule consists of nucellus and integument. Nucellus is essentially an ovule. In the middle part of the nucellus, one large megaspore cell (megaspore mother cell) separates, which divides meiotically and forms four haploid megaspores; three of them degenerate, and the remaining one divides repeatedly mitotically, forming a multicellular female gametophyte (called endosperm). From the two outer cells (near the micropyle) two highly reduced archegonia are formed, in which only egg. Fertilization occurs 20 months after the formation of the ovule.
After pollination of the scales of the female cone ( B ) close, and the male gametophyte continues its development on the megasporangium. When the male gametophyte grows towards the archegonium, the vegetative cell develops into a pollen tube, and the antheridial cell forms two cells: a stalk cell and a spermagen cell. They move into the pollen tube and reach the archegonium along it. Two sperm cells (male gametes lacking flagella) are formed from the nucleus of the spermogenic cell immediately before fertilization. Upon reaching the archegonium, the vegetative nucleus is destroyed, and one of the sperm fuses with the egg, and the other dies. From a fertilized egg - zygote (2n) the embryo develops (D ), surrounded by haploid endosperm, formed from the haploid female gametophyte and covered by the integument of the ovule.
This is how the seed is formed (E) gymnosperms - a diploid embryo, nourished by the primary haploid endosperm, protected by a skin (2n - ovule integument). Scots pine seeds ripen in the second year after pollination, and the following spring the scales separate and the seeds spill out.
The embryo consists of a suspension, a root, a stalk and cotyledons. Seed germination occurs under favorable conditions with the onset of spring in the temperate climate zone.
Conifers form natural landscapes - taiga over vast areas of continents. Their significance in the life of nature and in economic activity person is great. Being essential component biogeocenoses, they have enormous water conservation and anti-erosion significance. Coniferous plants provide the bulk of construction wood and are the source material for the diversified forestry industry. Viscose, silk, cellulose, staples, balsams and resins, pine wool and camphor, alcohol and acetic acid, tanning extracts, etc., as well as food products and vitamins are obtained from conifers. The seeds of some araucaria, cedar, and Siberian pine contain up to 79% oil, close to Provençal and almond oil. For the medical industry, conifers serve as raw materials for obtaining not only vitamins, but also the drug pinobin (an antispasmodic agent). Many types of conifers are used in folk medicine for the treatment of tuberculosis, nervous disorders, kidney diseases, bladder, hemorrhoids, deafness and as an antileprotic agent.
The needles and young shoots of some conifers are an indispensable winter food for moose, wood grouse eat needles, and many animals and birds feed on the seeds of Siberian cedar (as well as the seeds of other conifers). Juniper cones are food for black grouse. Yew wood is used to make expensive crafts and in the furniture industry; it is almost not susceptible to insects.
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Department Bryophytes. General characteristics.
- Modern bryophytes are represented by approximately 25 thousand species.
- Bryophytes - the only one in history flora line of evolution associated with the regressive development of the sporophyte. They represent a dead-end or blind branch of plant development.
- The vast majority are low-growing perennial plants ranging in size from 1 mm to several centimeters, less often up to 60 cm or more. The body of some bryophytes is a thallus or divided into stems and leaves. A characteristic feature is the absence of roots. Absorption of water and attachment to the substrate is carried out by rhizoids, which are outgrowths of the epidermis.
- Representatives of the department mostly inhabit wet habitats, as they are poorly adapted to life on land.
- There is a regular alternation of sexual and asexual generations.
Asexual and sexual reproduction of Bryophytes.
The development cycle is dominated by the haploid gametophyte. This is a specific feature of bryophytes compared to other higher plants. The gametophyte and sporophyte are one plant. The asexual generation (sporophyte) is the so-called sporogon (a small box with spores and a stalk, the lower part of which is turned into a sucker embedded in the body of the gametophyte). The sporophyte lacks independence and is completely dependent on the gametophyte.
The development of the sexual generation (gametophyte) begins from the moment of spore germination. First of all, a branched filamentous or lamellar formation develops protonema or preteen, on which the buds are formed. Stems with reproductive organs sprout from the buds. Genitals– gametangia (female – archegonia and male – antheridia ) multicellular. Large immobile eggs mature in archegonia, and independently moving spermatozoa mature in antheridia. During rain or heavy dew, the antheridia open and release numerous sperm, which, moving in drops of water covering the low tufts of the bryophytes, can reach the archegonium. The fusion of gametes and the further development of the zygote occurs inside the archegonium. At the top of the gametophyte stem, the zygote, over a period of several months to two years, gives rise to a sporophyte, ending in a capsule with spores. After the sporogon ripens, the capsule opens or falls off, and the spores spill out. The development cycle repeats. Spore formation is preceded by meiosis. Therefore, the spores, protonema and gametophyte are haploid. Only the zygote is diploid.
Classification of Bryophytes.
The bryophyte department is divided into three classes: anthocerotes, liverworts and phyllophytes. Leafy mosses are the largest class. It is divided into three subclasses: sphagnum mosses with one genus Sphagnum, andrea mosses and brie mosses (the largest subclass).
Sphagnums: brown deceptive protruding Magellan Andrey Skalnaya
Brie mosses. Polytrichum vulgaris or “cuckoo flax”
This is a species that forms turf in coniferous forests, in meadows, swamps, where it takes part in the formation of peat deposits. “Kukushkin flax” is the tallest moss. Its stem reaches a height of 50 cm. It grows in large cushion-shaped sods. The stem is densely covered with leaves. The plant spores abundantly. The box is located on a long stem, covered on top with an easily falling cap with thin, downward-pointing hairs that resemble linen yarn. Due to the formation of dense turf, Polytrichum vulgaris promotes surface accumulation of moisture and waterlogging of habitats.
Life cycle of Polytrichum vulgaris.
Subclass Sphagnum. Sphagnum mosses.
The Sphagnum subclass includes the only genus Sphagnum, which unites about 300 species. Species of the genus Sphagnum are large, soft, whitish-green, brown or reddish mosses. Most often these are plants of wet habitats, usually forming cushion-shaped turfs. Stem without rhizoids. At the top of the stem the branches are collected into a head. Sporophytes are red or brown almost spherical boxes that rise to pseudopod , which is part of the gametophyte and reaches 3 mm in length.
The anatomical structure of the branches is similar to the structure of the stem, however, in the place where the leaves are attached to the branches, in almost all species, peculiar water-collecting retort-shaped cells are formed. The leaves are single-layered and consist of two types of cells: chlorophyll-bearing and colorless dead aquifer. Green cells are narrow, dead - have pores and thickened walls; they fill easily with water. The water-holding capacity of sphagnum mosses is approximately 20 times its dry weight (for comparison, cotton wool can only absorb 4-6 times its own weight in water). Due to their excellent absorbent properties, these mosses have been used in Europe since the 1880s. as a dressing material for wounds and abscesses, but since the First World War they have been almost completely replaced in this sense by cotton, probably due to the more neat appearance of products made from it. Gardeners mix peat moss into soil to increase its water-holding capacity and acidity.
The life cycle of Sphagnum is similar to that of Polytrichum.
Representatives of this genus form extensive peat bogs. According to the most conservative estimates, peat bogs cover at least 1% of the land. Growing annually top part shoot, the stem dies from below and “peats” (accumulates and becomes compacted). Thus, over many years, huge deposits of peat are formed. The process of peat formation occurs due to stagnant waterlogging, lack of oxygen and the creation of an acidic environment (pH) by sphagnum mosses
Meaning of Bryophytes.
Bryophytes are distributed everywhere except seas and highly saline soils, but everywhere they prefer the most moist habitats. They are especially widely represented in the tundra; their annual growth is insignificant: from 1-2 mm to several centimeters, but the total result is a rather significant increase in moss tufts. Mosses are perennial species, are usually not eaten by animals and decompose very slowly. Mosses are capable of accumulating many substances, including radioactive ones, absorbing moisture and holding it relatively firmly, and therefore mosses are given special role in nature, primarily in regulating its water balance. Developing intensively, mosses worsen the productivity of agricultural lands, causing them to become waterlogged. But at the same time, they help convert surface water flow into underground water, protecting soils from erosion.
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A flower is a shortened, modified shoot of angiosperms, specialized for the formation of spores and gametes, as well as for the sexual process, which results in the development of a fruit with seeds.
Let's start classifying the parts of the flower. The flower consists of:
- The stem part, in which stands out:
- Pedicel - branching of the stem on which the flower is located
- Receptacle - the expanded upper part of the peduncle, from which sepals, petals, stamens, and pistils extend
- Leaf part, which is divided into:
- Sepals - modified leaves that make up the calyx of a leaf
- Petals - internal modified leaves that make up the corolla of the leaf
- Generative part, including:
- Stamens are the male reproductive organ of a flower, consisting of a filament and an anther, in the nests of which pollen is formed. Each pollen grain contains 2 haploid cells: vegetative and generative.
- The pistil, the main part of the flower located in the center, is the female reproductive organ.
Note that in botany there is such a thing as perianth: this is the name given to the outer part of the flower surrounding the reproductive organs. Typically, the perianth consists of an outer ring of sepals (calyx) and an inner ring of petals (corolla).
It consists of the ovary - the lower thickened part of the pistil, from which the fruit is subsequently formed, the style - the central part of the pistil between the ovary and the stigma, and the stigma itself - the wide upper part of the pistil, which receives pollen.
In the ovary of the pistil, ovules are formed, which, after pollination and fertilization, form seeds. There are flowers with an upper ovary - potatoes, peas, radishes, cloves, and flowers with a lower ovary - in cucumbers, bells, sunflowers. The superior ovary is free and easy to separate from the flower. It is much more difficult to isolate the lower ovary without damaging the flower, since it grows together with the stamens, perianth leaves, and even with the receptacle (in cucumber).
Particularly note the presence of nectaries (honey cakes) in the flower. They attract pollinating insects by secreting nectar - a sugary juice with a characteristic odor. When trying to collect nectar, insects shake the generative part of the flower, scattering pollen on themselves, on the stigma (due to which pollination occurs) and on other parts of the flower. The insects themselves serve as pollinators, transferring pollen from one flower to another on their body and limbs.
Perianth
Together, the sepals and petals make up the perianth. The perianth of the flower is double and simple. A double perianth includes a calyx and a corolla, found in apple trees, peas, and potatoes. If the perianth is not divided into a calyx and corolla, then it is called simple. A simple perianth consists of leaflets, characteristic of onions, oaks, birches, tulips and lilies of the valley. Some plants have no perianth, their flowers are called “naked”: poplar, willow.
Cup
The calyx is the outer part of the perianth formed by the sepals. The structure of the calyx varies from plant to plant. Highlight:
- Separate calyx - consists of sepals separated from each other: in wild radishes, strawberries
- Composite calyx - sepals are fused together: in cloves, peas
whisk
Whisk - inner part double perianth, formed by petals and usually brightly colored. The structure of the corolla may be different. The whisk can be:
- Free-petalled - the petals of the corolla are separated from each other
- Spinopetalous - the petals of the corolla grow together
In the future, as we study the families of angiosperms, we will study flower formulas. Remember now that if any parts of the flower grow together, then in the flower formula their number is taken in brackets.
Flower symmetry
Based on the symmetry features of the flower, they are divided into:
- Regular (actinomorphic), through which many planes of symmetry can be drawn. Regular flowers are found in carnations, lilies, and cucumbers. In the formula, such flowers are indicated by *
- Irregular (zygomorphic), such flowers have only one plane of symmetry. Flowers of this type are found in peas, sage, and snapdragons. In the formula, such a flower is indicated by the sign
Bisexual flowers have both stamens and pistils in one flower. However, there are plants in which the stamens and pistils are located on different flowers. Such plants have either stamens (staminate flowers) - male flowers, or pistils (pistillate flowers) - female flowers. Depending on the arrangement of male and female flowers, these plants are divided into:
- Monoecious - they have both male and female flowers located on the same plant: corn, birch, pumpkin.
- Dioecious - have both female and male flowers located on different plants: poplar, hemp, willow.
I will share my own association so that you can successfully remember these concepts. Imagine that a large number of guests came to visit wealthy owners. Rich owners have built two houses on the property, and they have the opportunity to separate all the guests, so that the men separate from the women and go to different houses ("dioecious plants"). If the hosts happen to be less wealthy, then they have only one house, so both male and female guests will have to look for a place to spend the night in the same house (“monoecious plants”).
Ovule
Also called ovule. It is a multicellular organ formed in the ovary from which the seed develops. The tissues of the ovary form a protrusion (outgrowth) called the placenta, which attaches the ovule inside the ovary. The ovule communicates with the placenta using the peduncle.
The process of megasporogenesis occurs in the ovule, which we will dwell on in more detail:
Pollination
Pollination is the process of transferring pollen from the anthers to the stigma (in flowering plants) or to the ovule (in gymnosperms). In the study of any topic, classification is an important aspect. There are two types of pollination:
Fertilization
Fertilization is the fusion of a sperm, sperm (male reproductive cell) with an egg, ovum (female reproductive cell), leading to the formation of a zygote. In one way or another, pollen (pollen grain) ends up on the stigma. The vegetative cell begins to grow into the pistil tissue, dissolving them and forming a pollen tube. Two sperm are formed from the generative cell.
The pollen tube grows into the embryo sac, allowing the sperm to reach the egg. Next, a unique phenomenon occurs in flowering plants, discovered by S.G. Navashin - double fertilization. As you remember, two sperm were formed from the generative cell. The essence of double fertilization is that one of the sperm fuses with the egg (fertilizes it) to form a zygote (diploid), from which the embryo develops. The second sperm fuses with the central cell (this cell is already diploid at the time of fusion) to form endosperm (triploid) - a reserve nutrient.
After fertilization, seeds are formed from the ovules over time. The seed coat is formed from the integument of the ovule (from the Latin integumentum - cover, covering). The pericarp is formed from the walls of the pistil ovary.
Inflorescences
Flowers, especially in insect-pollinated plants, are rarely arranged singly. Most often, flowers form clusters - inflorescences. An inflorescence is a part of the annual shoot of a plant, bearing flowers and modified bracts, in the axils of which the flowers or inflorescences are located.
We will also study this section using classification. Inflorescences are divided into:
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Plants are eukaryotic photosynthetic autotrophic organisms. The plant kingdom has about 500 thousand species.
The listed differences between plants and animals are not absolute. Features of animal organization are often found in lower plants, which correspond to the early stages of evolutionary development. For example, the ability for both autotrophic and heterotrophic nutrition (green euglena). More highly organized plants differ quite clearly from animals.
Plants are divided into lower and higher. U lower plants the body (thallus or thallus) is not divided into tissues and organs. These include Red Algae (Purple Algae), True Algae and Lichens. U higher plants the body is divided into organs (root, stem, leaf) formed by differentiated tissues. Higher plants include Bryophytes, Mocophytes, Horsetails, Ferns, Gymnosperms and Angiosperms (Flowers). The first four divisions are dispersed by spores ( spore
), the last two - using seeds ( seed
).
Plant propagation. All higher plants are characterized by alternation in the life cycle of sexual and asexual reproduction and the associated alternation of generations (development phases) - haploid (n) (gametophyte) and diploid (2n) (sporophyte). On sporophyte
sac-like formations appear - sporangia (organs of asexual reproduction), in which, as a result, sporogenesis
accompanied by meiotic division, haploid cells are formed disputes
. From the spores develops gametophyte
. Special reproductive structures are formed on it - gametangia
(organs of sexual reproduction) in which they are formed gametes
.
The male genital organs where sperm are formed are called antheridia
, the female genital organs where eggs are formed are called archegonia
. If both archegonia and antheridia develop on a gametophyte, it is called bisexual
, if only antheridia, then male
, if only archegonia, then female.
When gametes fuse, it is formed zygote
. A sporophyte develops from a zygote.
Department Angiosperms (Flowering)
Angiosperms- evolutionarily the youngest and most numerous group of plants. The department includes about 250 thousand species. Angiosperms grow in all climatic zones, constitute the bulk of the plant matter of the biosphere and are the most important producers (producers) of organic matter on land.
The dominant role of flowering plants is due to a number of progressive features:
- Appearance flower- an organ that combines the functions of asexual reproduction (spore formation) and sexual reproduction (seed formation).
- Formation within a flower ovaries, which contains the ovules (ovules) and protects them from adverse environmental influences.
- Formation from the ovary fetus: the seeds are located inside the fruit and are therefore protected (covered) by the pericarp. In addition, the fruit allows the use of various agents for seed dispersal (insects, birds, bats, as well as air and water flows).
- Double fertilization, as a result of which a diploid embryo and triploid (and not haploid, as in gymnosperms) endosperm is formed.
- Maximum gametophyte reduction. The male gametophyte - pollen grain - consists of two cells: vegetative and generative, which divides to form two sperm. The female gametophyte consists of eight embryo sac cells, one of which becomes the egg.
- Reproduction and seeds, And vegetative organs.
- Complication and high degree differentiation of organs and tissues. In particular, the most perfect conducting system: The xylem is represented by vessels, not tracheids; in the phloem, sieve tubes have a segmented structure, and satellite cells appear.
- Rapid growth and development processes in annual forms.
- Big variety of life forms: trees, shrubs, shrubs, subshrubs, perennial herbs, annual herbs, etc.
- Can form complex multi-tiered communities thanks to great variety life forms.
The importance of angiosperms in human life is difficult to overestimate. Almost all cultivated plants belong to this division. Angiosperm wood is used in industry, construction, paper making, furniture, etc. Many flowering plants are used in medicine.
