A. Ecological groups of plants in relation to humidity

The presence of 50 to 93% water in plant tissues indicates its extremely important importance in plant life. It has been established that cereals and sedges contain less water than representatives of the legume family and the forb group.

Moisture conditions determine the physiological and biochemical processes occurring in plants. With a lack of moisture, plants form a deeply penetrating but weakly branched root system and a small leaf surface area. Under conditions of insufficient water supply, the intensity of tillering and shoot-forming ability are weakened, and the period of transition of plants from the vegetative to generative phase is extended. The drier the air (greater humidity deficit), the greater the evaporation and the more water is consumed to build a unit of dry matter (transpiration). Some plants are able to tolerate soil and atmospheric drought. The ability of plants to maintain vital activity when there is a lack of air and soil humidity is called drought tolerance. Wheatgrass, feather grass, common grass, tall ryegrass, and rhizomeless wheatgrass are drought-resistant.

In the process of evolution, ecological types adapted to certain conditions of the water regime were formed. Among meadow plants, hygrophytes, xerophytes and mesophytes are distinguished.

Hygrophytes- plants growing in conditions of excessive moisture (river banks, lakes, swamps, wet meadows). They are distinguished by a well-developed above-ground mass and a poorly developed root system. They reproduce mainly by vegetative means; are characterized by low nutritional value, although they are used for livestock feed. Hygrophytes include common reed, water manna, yellow arctophila, fescue reed, water and slender sedge, lake reed, rush grass, marsh and swamp horsetail. Hygrophytes are also found in the group of forbs. In most cases, these are poisonous and harmful plants (marsh marigold, poisonous buttercup, poisonous wech, Lobel's hellebore).

Xerophytes- plants that grow in conditions of lack of moisture and can tolerate soil and air drought. They are widespread in areas of dry and hot climates (dry steppes, deserts and semi-deserts). Xerophytes have a powerfully developed root system, which allows them to use moisture from deep horizons; small leaves, often covered with a waxy coating or “hairs that reduce evaporation.” In some cereal plants (furrowed fescue, feather grass, thin-legged slender) evaporation is reduced by rolling the leaves into a tube when drought occurs. In xerophilic plants, the leaves are often modified into spines, which protect them from overheating.

Using moisture reserves, xerophytes grow quickly in the spring, and their consumption during this period is good. When drought occurs, the growth and development of these plants fade, the feed mass becomes dry, and its palatability decreases sharply.

In the group of xerophytes there are Succulents And Sclerophytes. Succulents are characterized by having succulent, fleshy stems and leaves that store water for the plant to use as needed. These include: cactus, aloe, sedum, juicy solyanka. Sclerophytes are not able to store water in their tissues; their leaves and stems are dry. These include: various types of wormwood and astragalus, camel thorn, saxaul, furrowed fescue, feather grass, thin-legged slender grass, etc.

In the tundra and suitable areas grow plants that have adapted to wet and cold soils (white grass, meadow grass, variegated fescue, small shrubs). In contrast, cryophyte plants grow on cold but fairly dry soils.

Mesophytes occupy an intermediate position between xerophytes and hygrophytes. These are plants that require sufficient, but not excessive moisture. The optimal soil moisture for their growth and development lies within 75-80% of PV. They are common in forest, forest-steppe zones, mountainous areas, floodplain and estuary meadows of all zones.

Mesophytes are characterized by good foliage compared to xerophytes. The leaves are thin, wide, not fleshy, pubescence is weak or absent. Plants growing on sufficiently moist soils form a shallow root system, while on drier soils they form a deeply penetrating root system. Most mesophytes have good feeding qualities, although there are poisonous and harmful plants among them. Mesophytes include most meadow cereals and legumes.

Along with the main types, there are transitional types from mesophytes to xerophytes and hygrophytes. In appearance they are closer to mesophytes, and in biology and ecology - to xerophytes or hygrophytes. Meso-xerophytes are: wheatgrass, yellow alfalfa, mountain clover, sainfoin, as well as ephemerals and ephemeroids, which complete their development cycle in the spring and have a short growing season. Meso-hygrophytes are: reed canarygrass, meadow foxtail, marsh bluegrass, common beckmania, marsh chin.

Meadows located in river floodplains, lowlands, and depressions are flooded in spring, and sometimes in summer or autumn, by flood waters or surface runoff waters. Plants react differently to the duration of flooding. Some of them die during prolonged flooding; in others, after the water subsides, the old shoots die off and are replaced by new ones. The ability of plants to maintain vital activity after prolonged excessive moisture is called moisture resistance.

A. M. Dmitriev distinguishes between plant resistance to flooding by hollow waters and resistance to flooding from below, from under the soil. According to their resistance to flooding by hollow waters, they are distinguished:

1. weakly resistant, withstanding flooding for no more than 2-5 days (urchin grass, wheatgrass, perennial ryegrass, sainfoin);
2. medium-resistant - up to 6-15 days (red fescue, meadow timothy, blue alfalfa, red clover, meadow rank);
3. quite stable - from 15 to 30 days (meadow and swamp bluegrass, meadow fescue, yellow alfalfa, pink and white clover, horned grass, vetch, mouse pea);
4. especially resistant - from 30 to 45 days or more (white bentgrass, meadow foxtail, common beckmania, reed canarygrass, awnless bromegrass, creeping wheatgrass, slender sedge, swamp grass).

Plants withstand spring flooding by hollow waters much better than summer and autumn flooding. This is due not only to the fact that the plants are in the initial stage of development, but also to the fact that spring waters are richer in oxygen.

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All plants are diverse; they grow almost all over the planet and in any conditions. And depending on the conditions to which certain species are best adapted, they are grouped into ecological groups of plants.

What it is?

Ecological groups of plants are collections of species that have similar needs for the value of some factor, for example, moisture, light, etc. In addition, plants of one specific group have some common characteristics that arose during evolution in the process of adaptation of the organism to certain environmental conditions. Accordingly, plants of different ecological groups can differ radically from each other.

The boundaries that exist between different groups are quite arbitrary.

What environmental protections exist?

All plants are divided into groups, as noted above, depending on the need for a particular factor.

So, the division of plants into ecological groups is based on their need for:

• light;
• moisture;
• a certain temperature;
• soil trophicity;
• soil acidity;
• soil salinization.

Using the same principle, it is possible to classify not only wild plants, but also to identify ecological groups of indoor plants. The principle will be exactly the same. In addition, knowing exactly which group a particular flower belongs to, you can provide it with proper care.

Main ecological groups of plants depending on moisture needs

According to this, three groups of plants can be distinguished:

• hydrophytes;
• mesophytes;
• xerophytes.

Hydrophytes - those that grow in water. In most cases, they grow in fresh water bodies, but can even be found in salt water.

This ecological group includes plants such as reeds, rice, reeds, sedges, arrowheads, etc.

Hylatophytes can be classified as a separate subgroup of aquatic plants. These are representatives of the flora that have weak stems and therefore cannot grow outside the aquatic environment. The main part of such a plant (leaves and flowers) is located on the surface of the reservoir and is held by water. Hylatophytes include water lilies, lotuses, water lilies, etc.

Mesophytes are plants that prefer average humidity. These include almost all widely known plants, including those that are most often grown in gardens and vegetable gardens.

Xerophytes are representatives of the flora that are adapted to exist in arid areas. These include wheatgrass, sand-lover, as well as cacti, including indoor ones.

Depending on the need for light

According to this principle, plants can be divided into three groups:

• heliophytes;
• scioheliophytes;
• sciophytes.

The first are plants that require bright light.

Scioheliophytes are able to tolerate shade, but also grow well in sunny areas. Among indoor plants of this type, monstera can be distinguished. Among the wild ones are willow, birch, and aspen. Cultivated plants of this group are turnips, radishes, parsley, mint, lemon balm, cucumbers, zucchini, asparagus, lettuce, rhubarb, and sorrel.

Sciophytes are They will not grow well in overly bright light. These include all algae, as well as mosses, lichens, mosses, and ferns.

Ecological groups depending on the required temperature

There are four groups of plants:

• hekistothermophytes;
• microthermophytes;
• mesothermophytes;
• megathermophytes.

The first are very frost-resistant plants. They grow in the northern part of the planet.

Microthermophytes are representatives of the flora that are able to tolerate significant cold, but not severe frosts.

Mesothermophytes love warmth, while megathermophytes can tolerate significant heat.

Dependence on soil type

Here, ecological groups of plants are distinguished according to three different factors.

The first is the trophicity of the soil. This is the saturation of the soil with nutrients, as well as macro- and microelements. Based on this factor, plants are divided into oligotrophs, mesotrophs, and eutrophs. Oligotrophs can grow on poor soils, mesotrophs prefer moderately fertile ones, and eutrophs grow exclusively on chernozems and other types of soils with high fertility.

Depending on the salinity of the soil in which they grow, plants are divided into two groups: halophytes and glycophytes. The former are able to tolerate soil salinity, while the latter are not.

Finally, depending on the pH level of the soil, plants are divided into three ecological groups: neutrophytes, acidophytes and basophytes. The former prefer soil with (close to 7). Acidophytes grow in highly acidic soils. And basophytes prefer alkaline soils.

So we looked at all the environmental groups that belong to them.

Hydatophytes- These are aquatic plants that are completely or almost entirely submerged in water. Among them are flowering plants that have secondarily switched to an aquatic lifestyle (elodea, pondweed, etc.). They have reduced stomata and no cuticle. Shoots supported by water often do not have mechanical tissues; aerenchyma is well developed in them. The root system of flowering hydatophytes is greatly reduced, sometimes completely absent or has lost its main functions (in duckweeds). Absorption of water and mineral salts occurs over the entire surface of the body.

Hydrophytes- these are terrestrial-aquatic plants, partially submerged in water, growing along the banks of reservoirs, in shallow waters, in swamps. They have better developed conductive and mechanical tissues than hydatophytes. Hydrophytes have an epidermis with stomata, the rate of transpiration is very high, and they can grow only with constant intensive absorption of water.

Hygrophytes- terrestrial plants that live in conditions of high air humidity and often on wet soils. Due to high air humidity, transpiration may be difficult for them, so to improve water metabolism, hydathodes, or water stomata, secrete droplet-liquid water, develop on the leaves. The leaves are often thin, with a shadowy structure, with a poorly developed cuticle, and contain a lot of free and poorly bound water. The water content of tissues reaches 80% or more.

Mesophytes can tolerate short and not very severe drought. These are plants that grow with average moisture, moderately warm conditions and a fairly good supply of mineral nutrition.

Xerophytes They grow in places with insufficient moisture and have adaptations that allow them to obtain water when there is a shortage of it, limit the evaporation of water, or store it during drought. Xerophytes are better able to regulate water metabolism than all other plants, and therefore remain active during prolonged drought.

Xerophytes are divided into two main types: succulents and sclerophytes. Succulents- succulent plants with highly developed water-storing parenchyma in various organs. The leaves, and in the case of their reduction, the stems of succulents, have a thick cuticle, often a thick waxy coating or dense pubescence. Sclerophytes - uh then the plants, on the contrary, are dry in appearance, often with narrow and small leaves, sometimes rolled into a tube. The leaves may also be dissected, covered with hairs or a waxy coating. Sclerenchyma is well developed, so plants can lose up to 25% of moisture without wilting without harmful consequences. The suction power of the roots is up to several tens of atmospheres, which allows you to successfully extract water from the soil

Ecological groups of animals in relation to water:

Among a number of groups of animals, one can distinguish hygrophilic (moisture-loving - mosquitoes), xerophilic (dry-loving - locusts) and mesophilic (preferring moderate humidity). Methods for regulating water balance in animals can be divided into behavioral (digging holes, searching for watering places), morphological (formations that contribute to the retention of water in the body - shells, keratinized integuments of reptiles) and physiological (the ability to form metabolic water, saving water during excretion).

The formation of metabolic water is the result of metabolism and allows you to do without drinking water. It is widely used by insects and some animals (camels). Poikilothermic animals are more hardy because... they do not have to use water for cooling, like warm-blooded animals.

Topography (relief). The relief is divided into macrorelief (mountains, intermountain depressions, lowlands), mesorelief (hills, ravines), microrelief (small irregularities).

The main topographic factor is height. With altitude, average temperatures decrease, daily temperature differences increase, precipitation, wind speed and radiation intensity increase, atmospheric pressure and gas concentrations decrease. As a result, vertical zoning is formed.

Mountain ranges can serve as climatic barriers; the leeward side of the mountains receives less precipitation; In addition, mountains can play the role of an isolating factor, limiting the migration of animals and plants. The intensity of light and temperatures on the southern slopes (in the Northern Hemisphere) is higher. An important topographical factor is the steepness of the slope. Steep slopes (slope above 35 degrees) are characterized by soil washing away.

Edaphic environmental factor – soil. This factor is characterized by chemical components (soil reactions, salt regime, elementary chemical composition of the soil); physical (water, air and thermal regimes, soil density and thickness, its structure); biological (plant and animal organisms inhabiting the soil).

The availability of moisture depends on the water-holding capacity of the soil, which is higher the clayier and drier the soil. Temperature depends on the external temperature, but, due to the low thermal conductivity of the soil, the temperature regime is quite stable; at a depth of 30 cm, the amplitude of temperature fluctuations is less than 2 degrees.

By acidity reactions soils distinguish between groups of plants: acidophilic– grow on acidic soils; basophilic– at alkaline pH more than 7; neutrophilic– pH 6-7; indifferent– can grow in soils with different pH.

Salted Soils with excess content of water-soluble salts (chlorides, sulfates, carbonates) are called. Plants that grow in saline soils are called halophytes. Nitrophils– plants prefer soils rich in nitrogen.

An important environmental factor, often limiting, is the presence in the soil of the necessary mineral salts - macro- and microelements

Environmental indicators. Organisms that can be used to determine the type of physical environment in which they grew and developed are environmental indicators. For example, halophytes. Adapting to salinity, they acquire certain characteristics; based on their presence, we can conclude that the soil is saline.

It is known to use geobotanical methods to search for minerals. Some plants are capable of accumulating chemical elements and based on this we can draw conclusions about the presence of this element in the environment.

An important living indicator are lichens, which grow in clean places and disappear when atmospheric pollution appears. The qualitative and quantitative composition of phytoplankton makes it possible to assess the degree of pollution of the aquatic environment.

Other physical factors. Other abiotic factors include atmospheric electricity, fire, noise, the Earth's magnetic field, and ionizing radiation.

Adaptation of organisms to the influence of factors. Living organisms adapt to the influence of periodic factors, that is, they adapt. At the same time, adaptation covers both the structure and functions of organisms (species of individuals, their organs). Organisms adapt to changing conditions in their habitat under the influence of variability, heredity and natural selection. The adaptation of organisms to the influence of factors is hereditarily determined. They were formed historically and evolutionarily and changed along with changes in environmental factors. In this case, organisms, first of all, adapt to periodically influencing factors. The source of adaptation is genetic changes - mutations that arise both under the influence of natural factors and as a result of artificial influence. The accumulation of mutations can lead to disintegration processes, but thanks to selection, mutations serve as a factor in the adaptive organization of living organisms.

Adaptation of organisms to the influence of a complex of factors can be successful. For example, the adaptation of the short ancestor of the horse over 60 years led to the modern tall, beautiful and fleet-footed animal, and unsuccessful, for example, the extinction of mammoths (tens of thousands of years ago) as a result of the Quaternary glaciation, the vegetation on which these animals, well adapted to low temperatures, fed, disappeared.

According to some researchers, primitive man, who used mammoths as a hunting object, was also to blame for the disappearance of mammoths.

In modern conditions, in addition to natural limiting environmental factors, new factors limiting the existence of living organisms are being formed that have arisen as a result of human activity. For example, new synthetic chemicals that were not previously present in the habitat of organisms (herbicides, pesticides, etc.), or an increase in excessively large quantities of existing natural environmental factors. For example, an increase in CO 2 content in the atmosphere as a result of the operation of thermal power plants, boiler plants and vehicles. Nature is unable to utilize the ever-increasing amount of CO 2 emitted into the atmosphere, which leads to pollution of the habitat of organisms and an increase in the temperature of the planet. Pollution leads to changes in the physical, chemical and biological properties of the living conditions of organisms, impoverishes biodiversity, and undermines human health.

Some environmental factors are light, temperature, air humidity, precipitation, wind, etc.

Regarding the need for light three ecological groups of plants can be distinguished: 1. light plants, or heliophytes– plants of open spaces. This includes, for example, feather grass, most cultivated plants: sugar beets, potatoes, 2. shade-tolerant plants, or hemisciophytes. They can tolerate a lot of shade, for example, hedgehog's team 3. shade-loving plants – sciophytes do not tolerate full light, for example, wood sorrel, sedmichnik.

Plant growth is directly related to temperature. Clearly differentiated thermophilic(from Greek thermo– warmth, philos – love) plants and their antipodes are cold-tolerant, or cryophilic(from Greek Krios- cold). A. Decandolle (1885) identifies groups of hekistothermic, microthermal and megathermic plants (from Greek hekistos- cold, micros– small, megas- big).

Plants according to their characteristic water regime They are divided into hydrophytes, helophytes, hygrophytes, mesophytes, and xerophytes.

Hydrophytes(from Greek gidora– water, phyton- plant) - aquatic plants that freely float or take root at the bottom of a reservoir and are completely submerged in water. Examples of floating hydrophytes are Canadian elodea, floating pondweed, white water lily, and yellow water lily. These plants are characterized by a strong development of air-bearing tissue - aerenchyma, and a large number of stomata on floating leaves. Poor development of mechanical tissues, sometimes variegated leaves.

Helophytes(from Greek gelo- swamp, phyton- plant) aquatic - terrestrial plants that grow both in water in shallow waters and along waterlogged banks of rivers and reservoirs, and can also live on abundantly moist soil away from reservoirs. Helophytes include common reed, chastukha, arrowhead, and susak.

Hygrophytes(from Greek hygros– wet, phyton– plant) – terrestrial plants growing in conditions of high soil and air humidity. Their tissues are saturated with water up to 80% and higher, and there are water stomata. Hygrophytes include common wood sorrel, round-leaved sundew, marsh bedstraw, and rice. Hygrophytes are characterized by poor adaptation to the regulation of their hydration. Therefore, picked plants from this group wither very quickly.

Mesophytes(from Greek mesos – average, phyton– plant) - plants adapted to life in conditions of average water supply. They can tolerate short and not very severe droughts. The vast majority of plants in forests and meadows belong to this group.

Xerophytes(from Greek xeros- dry, phyton– plant) – plants adapted to life in conditions of low water supply. They are able to tolerate soil and atmospheric drought, as they have various adaptations for living in hot climates with very little precipitation. Most xerophytes have adaptations that limit transpiration: leaflessness, small leaves, pubescence, summer leaf fall.

Ecological significance of wind in forest ecosystems is associated with the transfer of not only pollen and spores, but also small seeds . Anemophilous(from Greek anemos- wind, fillet- I love) plants produce a huge mass of fine dry pollen. All gymnosperms and about 10 percent of angiosperms belong to anemophilous plants. U anemochoric p asthenia (from Greek anemos- wind, choreo-advancing) of plants, all sorts of outgrowths are formed on the seeds or fruits: crests, lionfish, parachutes. The next adaptation is the formation of very small and light seeds, for example, the seeds of broomrapes, orchids, as well as the “tumbleweed” adaptation, for example, in kermeks.

Questions for self-study

1.Botany and objects of its study. Similarities and differences between plants and animals. The concept of plant ecology.

2. Plant cell, its organelles, distinctive features of plant and animal cells.

3. Cell of prokaryotes and eukaryotes, similarities and differences.

4. Plant integumentary tissues: primary and secondary. Functions of integumentary tissues.

5.Mechanical tissues, their location in the plant body, functions of mechanical tissues.

6. Conductive tissues of plants, their functions and structure.

7.Phloem as a complex tissue. Functions of phloem.

8. Plant storage tissues, their functions and location in the plant body.

9.Aerenchyma, its functions and location in the plant body.

10.Root. Functions. External and internal structure.

11.Types of roots. Types of root systems, the influence of environmental factors on their size and placement. Modification of roots.

12.Escape. Structure and types of shoots. Branching and growth.

13.Kidney. The structure and variety of kidneys.

14.Modifications of shoots.

15.Stem. Functions. Features of the internal structure of the stems of monocotyledonous and dicotyledonous herbaceous plants.

16.Features of the structure of the stem of a woody plant.

17.Leaf morphology.

18. Internal structure of leaves. Sheet functions. Photosynthesis.

19. The influence of environmental factors on the external and internal structure of the stem and leaves.

20. Life expectancy of leaves. Leaf fall.

21. Flower. Structure. Functions of flower parts.

22. Pollination.

23. Double fertilization. Formation of seed and fruit.

24.Types of inflorescences and their biological significance.

25. Fruits. Classification of fruits.

26.Structure of seeds. Types of seeds. Conditions necessary for seed germination.

27. Distribution of fruits and seeds.

28. General information about plant propagation.

29. Vegetative propagation.

30. The concept of plant growth.

31. Environmental factors of plants.

32. Ecological groups of plants.

33. Life forms of plants.

34. The concept of flora and vegetation. Plant habitats. Floristic areas.

35. Plant systems. Taxonomic units. Characteristics of lower and higher plants.

36. Bacteria and cyanobacteria. Features of the structure. Meaning.

37. Algae. Characteristics of algae departments. Meaning.

38. Mushrooms. Characteristics of classes. Meaning.

39. Lichens. Features of the structure. Meaning.

40. Bryophytes. Characteristics of the department, its division into classes.

41. Ferns. Characteristics of mosses, horsetails, ferns.

43. Angiosperms. Characteristics of the department, its division into classes.

44.Characteristics of the families Ranunculaceae, Rosaceae, and Legumes.

45. Characteristics of the families Apiaceae, Cruciferae, Solanaceae, Asteraceae.

46.Characteristics of the lily and cereal families.

47. The concept of plant communities.

48. Patterns of distribution of plant communities in natural zones on the territory of the Russian Federation. Tundra vegetation.

49.Vegetation of the forest zone of the Russian Federation.

51. Vegetation of the steppe zone of the Russian Federation.

52. Vegetation of meadows and swamps.

53. Desert vegetation.

54. The importance of plants in nature and human life. Indoor plants.

Publication date: 2014-11-03; Read: 3505 | Page Copyright Infringement | Order writing a paper

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There are different living conditions on Earth: somewhere it is warm and dry, somewhere there is high humidity, in some places there is a pronounced change of seasons, in others there is permafrost, etc. Plants have been able to adapt to most living conditions, various vegetation can be found almost everywhere. At the same time, plants have their own adaptations to each specific habitat. For example, plants in tropical forests and deserts have completely different adaptations to climatic conditions. In addition, even in the same forest, living conditions are very different. This way the trees receive enough light, but the grasses do not. In this regard, various ecological groups of plants are distinguished.

Ecological groups in relation to light

Light-loving plants can grow normally only in well-lit areas. These include many trees, steppe and meadow grasses. Light-loving trees growing in open areas look different than trees of the same species growing in the forest. Single trees are not very tall and have a large crown; branches grow not only in the upper, but also in the lower part of the trunk. Trees living in the forest have a crown only at the top of the trunk. This difference is due to the fact that in the forest there is not enough light for light-loving trees; the lower branches cannot carry out photosynthesis normally and die.

The leaves of light-loving plants have a lighter green light, since they do not have as many chloroplasts. Sunlight is effectively captured by such a quantity. Often the leaves are covered with a waxy coating, have many stomata, and are positioned with an edge towards the sunlight. Such devices reduce their overheating.

Shade-loving plants can grow and develop normally only in the shade. They live under the forest canopy. Their leaves are thin with a small number of cell layers, since light almost does not penetrate into the thickness of the leaf. The leaf color is dark green. This suggests that there are many chloroplasts in leaf cells. Thus, every ray of light that hits the sheet is captured.

Shade-loving plants are characterized by poor development of mechanical and conductive tissues. These are usually small plants.

Shade-tolerant plants prefer to grow in good light, but can also grow in the shade. Many trees of deciduous forests belong to this group. In such trees, branches grow throughout the entire trunk, and not just at the top, like in light-loving trees. The upper foliage has signs of light-loving vegetation (it is light, dense), the lower foliage is darker and thinner.

Environmental groups in relation to water

There are plants of aquatic, wet and dry habitats. Each group has its own adaptations to excess or lack of moisture.

For aquatic plants characterized by a large body surface. With a small mass, this increases their buoyancy. These plants absorb water not with roots (which they may not have at all), but with the entire surface of the body. Mechanical and integumentary tissues are poorly developed. Water is a denser medium, so there is no need for well-developed mechanical tissues that would provide additional support.

In aquatic plants, only those leaves that float on the surface have stomata, and on the upper side of the leaf.

The tissues of aquatic plants contain many intercellular spaces containing air. This makes it easier to breathe and absorb carbon dioxide for photosynthesis, since the water contains fewer gases.

For moisture-loving plants characterized by large leaves and many stomata. Such plants evaporate large amounts of water.

For plants of dry habitats(steppes, deserts) are characterized by a well-developed root system. They store water in the roots, stems (cactus) or leaves (aloe). The leaves have a dense skin, hairs, and a waxy coating. There are few stomata and they are located in recesses. All this reduces evaporation. Cacti have leaves that are turned into spines.

Ecological groups in relation to temperature

For temperate climate characterized by clearly defined seasons. By winter, most plants shed their leaves and enter a dormant stage, when all life processes slow down. In perennial grasses, the green surface parts die off during the winter.

Hot climate plants have devices that prevent them from overheating. If these are shade-loving plants growing in conditions of sufficient moisture, then they evaporate a large amount of water. Evaporation cools the plant. If plants grow in dry, well-lit places, then they cannot cool by evaporation. In addition, they have to conserve water, that is, try to reduce evaporation. In this case, it helps to reduce the leaf blades, turn them with their edges towards the Sun, curl the leaves in the daytime, modify the leaves into spines, and pubescent leaves that reflect sunlight. Many of these plants store water in various organs.

For plants of cold habitats Characterized by the small size of both the plants themselves and their leaf blades. Typically, such plants are no higher than the snow cover, which protects them from strong winds and cold. Plants in cold habitats usually grow horizontally, spreading along the ground.