What are higher plants in biology definition. What plants are called higher? Examples, signs and characteristics of higher plants

The figure shows psilophytes - extinct plants.

Using a fragment of a geochronological table, set the era and period in which these organisms appeared, as well as a possible ancestor at the plant division level.

Indicate by what signs psilophytes belong to higher spore plants.

Geological table

Explanation.

Let's use the table, in the third column we will find psilophytes; we determine from the second and first columns the era and period when the psilophytes lived

Answer:

1) Era: Paleozoic

Period: Silurus

2) The ancestors of psilophytes are multicellular green algae.

3) Signs of higher spore plants are:

Dividing the body into two parts - aboveground and underground

The presence of multicellular reproductive organs - sexual (gametangia) and asexual (sporangia)

Primitive conductive system, integumentary tissue

Note.

Psilophytes had a tree-like form, separate filamentous processes served them to attach to the soil and absorb water and minerals from it. Along with the formation of a semblance of roots, a stem and a primitive conducting system, psilophytes developed an integumentary tissue that protects them from drying out.

higher plants are multicellular phototrophic organisms adapted to life in ground environment and characterized correct alternation sexual and asexual generations and the presence of differentiated tissues and organs.

The main features that distinguish higher plants from lower ones:

Adaptability to living in a terrestrial environment;

The presence of clearly differentiated tissues that perform specific specialized functions;

The presence of multicellular reproductive organs - sexual (gametangia) and asexual (sporangia). The male gametangia of higher plants are called antheridia, and the female gametangia are called archegonia. Gametangia of higher plants (in contrast to lower ones) are protected by membranes of sterile (sterile) cells and (in certain groups of plants) can be reduced, i.e. reduced and simplified;

The transformation of a zygote into a typical multicellular embryo, whose cells are not initially differentiated, but are genetically determined to specialize in a certain direction;

The correct alternation of two generations - a haploid sexual (gametophyte), developing from a spore, and a diploid asexual (sporophyte), developing from a zygote;

Dominance in life cycle sporophyte (in all departments except Bryophytes);

The division of the sporophyte body (in most divisions of higher plants) into specialized vegetative organs - root, stem and leaves.

Source: USE - 2018, RESHU USE

Valeria Rudenko 15.06.2018 16:32

Hello. I don’t understand, but how should we determine the ancestor of plants? Why do we take multicellular green algae?

Natalya Evgenievna Bashtannik

We use biological knowledge, and according to the figure - weak differentiation of the body

Vasily Rogozhin 09.03.2019 13:39

Of course, the ancestors of psilophytes, like all higher plants, are not ancient green algae, but Chara algae, which now constitute an independent department.

And in addition to the answer about the differences between higher plants and lower plants, it is worth noting that "the presence of clearly differentiated tissues" is not absolute today. hallmark these groups of plants. Brown algae, for example, belonging to lower plants, have real tissues (tissue type of thallus differentiation). Here is the presence of organs - yes, this is a sign only of higher plants, and real tissues can be in both higher and lower plants.

Botany (from the Greek. " nerd"- greenery, grass) is the science of plants that studies their external and internal structure, the processes of their vital activity, the significance and distribution in nature, the interaction of plants and the environment.
Plants are ubiquitous on Earth. With the exception of the highlands and the poles, all land is covered with plant communities. The historically established set of plant species living in a certain area is called flora. It is usually divided into wild and cultivated. Aggregate plant communities(phytocenoses) of the Earth or its individual regions are called vegetation. The distribution of vegetation depends on habitat conditions (first of all, on the type of soil and climate) and obeys the laws of geographical zonality and zonality.

The main signs of plants

1. Autotrophic type of nutrition - plants are able to synthesize organic substances from inorganic substances in the process of photosynthesis.
2. Features of the cell structure: the presence of a rigid cell membrane of cellulose and pectin substances, a central vacuole, plastids. The cells of higher plants lack a cell center.
3. Absorption of substances only in the form of liquids or gases.
4. Inability to move (excl.: some unicellular algae).
5. Growth throughout life.

higher and lower plants

According to the morphological organization, two groups of plants are distinguished: higher and lower. The body of lower plants is not divided into organs and tissues, it is represented by one cell or thallus (multicellular formation). Most lower plants live in water. According to modern ideas, only algae belong to lower plants.
Higher plants have organs and tissues and predominantly live on land (although there are species that live in water). These include spores (bryophytes and ferns) and seed plants(gymnosperms and angiosperms).

The value of plants

1. The release of oxygen, necessary for the respiration of living organisms.

They convert the energy of the Sun into the energy of chemical bonds (cosmic role).

The initial link in the food chain.

2. Used for food.

Decorative.

Used in construction.

3. Raw materials for the textile, chemical, paper, perfume and cosmetic industries.

   Getting medication.

Plant life forms

The life form of a plant is the external appearance of a plant, reflecting its adaptability to certain environmental conditions. There are 4 main life forms:
The tree is perennial with one main stem (trunk) and a set of lateral shoots forming a crown. The stem is usually woody and erect. Life expectancy can reach several thousand years.
A shrub is a perennial plant with several stems (stems). The stem is usually also lignified and erect. The lifespan of an individual stem ranges from 2 (raspberry) to 20-25 years (hazel), but the total lifespan of the entire plant can be several hundred years. It should be noted that depending on the growing conditions, some plants can be either shrubs or trees (for example, mountain ash).
Shrubs are small shrubs that do not exceed 50 cm in height (10-30 cm on average). Often they have long rhizomes. The life expectancy of individual bushes is on average 5-10 years, the plant as a whole can exist for several hundred years. Shrubs include blueberries, lingonberries, cranberries, myrtle, heather.
Herbs are plants that have a non-lignified stem. In the temperate zone above-ground shoots grasses most often live only one growing season, after which they die off. By life expectancy, grasses are divided into annuals, biennials and perennials. Annual herbs in one season go through one or more development cycles from seed to adult plant, which dies after the formation of fruits (shepherd's purse, yarutka). Biennial grasses in the first year of existence form only vegetative organs, and in the second year they form generative organs and die after the formation of fruits (carrots, beets, cabbage). Perennial grasses live for several decades, annually forming new above-ground shoots that die off at the end of the growing season. TO perennial herbs includes most herbaceous plants. The biggest herb is the banana.

plant cell structure

A plant cell is characterized by the presence of a shell consisting of cellulose (fiber). The shell provides protection, strength of the cell and plant, the shape of the cell, and is involved in the transport of substances. Under the shell is the cytoplasmic membrane.
Inside the cell is the cytoplasm with a complex of organelles inherent in all eukaryotes, and the nucleus. It should be noted that the plant cell contains organelles that are not characteristic of other eukaryotes: the vacuole (filled with cell sap) and plastids.

Plant tissues

Tissue is a group of cells and intercellular substance similar in structure, origin and adapted to perform one or more functions.

Educational fabrics

They form new cells and ensure the growth of the plant. The ability to divide is retained only in the cells of these tissues. These tissues can persist throughout the life of the plant. All educational tissues consist of undifferentiated cells. Their cells are characterized small size, a thin shell, a relatively large core, occupying central position, the absence of a large central vacuole and chloroplasts. Allocate apical, lateral, intercalary and wound educational tissues.
Apical - located at the top vegetative organs(escape, root). They increase the corresponding organs in length.
Lateral - located in the stem and root (cambium and phellogen). They determine the growth of the body in thickness.
The intercalated ones are located at the bases of the internodes (in cereals). They provide fast growth escape are temporary.
Wound (traumatic) occur during the healing of damaged tissues and organs.

Integumentary tissues

They are located on the surface of plant organs. Functions: barrier, protection against drying, damage and eating by animals; gas exchange, evaporation of water, absorption of substances.

Epidermis - located on the surface of leaves, young stems, flowers. The cells of the epidermis are alive, transparent and very firmly connected to each other, the intercellular substance is practically absent. Outside is the cuticle (this is a substance consisting of vegetable waxes). The epidermis includes: basal cells (make up the bulk; often these cells have sinuous walls to increase strength); stomata (consist of guard cells with unevenly thickened membranes, between which there is a stomatal gap. This gap can change its lumen, regulating transpiration and gas exchange) and hairs.
The rhizodermis is the integumentary tissue of a young root. The cells are arranged in one row, they are living, with a thin membrane. In the absorption zone, rhizodermal cells form outgrowths - root hairs.
Periderm - formed on the stem and root and consists of several layers of cells. IN temperate climate in plants appears in mid-summer. Two parts are distinguished in it: cork (located on the surface of organs and makes up the bulk of the periderm; cork cells are dead and tightly adjacent to each other), phellogen (lateral educational tissue consisting of a single layer of cells; due to its work, the periderm grows in thickness. In the cork there are areas with loosely located cells - lenticels (serve for gas exchange).Lenticels are closed for the winter.
Bark - formed in most trees to replace the periderm. The crust is composed of alternating layers of cork and other dead bark tissue. All cortical cells are dead.

mechanical fabrics

Functions: protective, maintaining a certain position of organs in space. At aquatic plants mechanical tissues are poorly developed or not developed at all. There are two varieties - collenchyma and sclerenchyma. Collenchyma is the primary mechanical tissue of young shoots, which consists of living cells with unevenly thickened cell walls, which allows the organ to grow as a whole. Sclerenchyma consists of dead cells, with very thick, evenly thickened membranes. There are two main types of sclerenchyma: fibers and sclereids. The fibers are strongly elongated cells with a very thick membrane and a narrow cavity. The fibers that make up the phloem are called bast, and those that make up the xylem are called woody. Sclereids may be rounded, branched, or otherwise shaped.

Conductive tissues

The main function is the transport of substances throughout the plant. They include two groups - xylem (wood) and phloem (bast). Along the xylem from the bottom up (from the roots to the leaves - ascending current) water rises with minerals dissolved in it; organic substances synthesized in the roots also move along the xylem. Organic substances move from top to bottom along the phloem (descending current); but they can also move upwards (for example, to flowers, fruits, or to the top of a shoot). Often xylem and phloem are located together, forming vascular bundles.
Xylem is made up of the following cells:

1. Conductive elements: vessels and tracheids. Tracheids (in rhinophytes, ferns, gymnosperms and angiosperms) are strongly elongated cells with intact primary walls. Vessels (in angiosperms) - dead cells with a thick shell, between adjacent cells arise through holes, so the vessel resembles a tube.
2. mechanical fibers.
3. Storage elements are living cells.
4. Beam elements - formed by living cells, perform the function of transporting substances in the radial direction.

The phloem is made up of the following cells:

Conductive elements are sieve tubes. These are living cells, also forming a vertical row, on the transverse partitions there are many holes (perforations; therefore, this side resembles a sieve - hence the name). Near individual cells of the sieve tubes are satellite cells that provide nutrition to the conductive elements. Cells of conducting elements in a mature state do not contain a central vacuole and nuclei, but remain alive.

1. mechanical elements.
2. Spare elements
3. beam elements.

excretory tissues

Functions: removal of metabolic products and excess water; accumulation and isolation from other organs of metabolic products.

Main fabrics

Assimilation (photosynthetic) - responsible for photosynthesis. Consists of cells that contain big number chloroplasts. This tissue is found in leaves and young stems.

Storage - is most often found in the roots and shoots or in specialized bodies(tubers, bulbs or rhizomes).

Air-bearing is a tissue with highly developed intercellular spaces, the main function of which is ventilation. It is most strongly developed in plants immersed in water or living in a swamp.

Aquifer is a tissue that most often develops in plants that live in conditions of insufficient moisture (cacti, agaves, aloe). Its main function is to store water.

By appearance, in its structure and biological features higher plants are very diverse. These, in addition to flowering and gymnosperms, also include ferns, horsetails, club mosses and mosses. The main difference between gymnosperms and higher spore plants is seed propagation. The number of species reaches 300 thousand, and, according to some botanists, at least 500 thousand.

general characteristics

Higher plants have developed many various devices and properties for life in a variety of land conditions. Angiosperms have reached the greatest development and adaptability to a terrestrial way of life.

Signs characteristic of higher plants:

• Differentiation into organs and tissues;
• conducting system consisting of xylem and phloem;
• correct generational change;
• organs of sexual reproduction: antheridia and archegonia;
• the body of plants is characterized by a leaf-stem structure.

Grounds for dividing plants into higher and lower

All representatives of the plant world, depending on the structure, are divided into 2 groups - lower and higher.

The main criterion by which plants are classified as higher is the presence of a complex tissue structure. It is represented by conductive and mechanical tissues. Also a distinctive feature is the presence of tracheas, tracheids and sieve tubes, which quickly deliver nutrients from the root to the leaves, inflorescences, stems.

The lower ones, in turn, have a primitive structure, consist of one cell, there are multicellular organisms, the body of which is called a thallus. They are devoid of roots, stems, and leaves.

Lack of muscle and nerve tissue

Higher plants are a group of living organisms that occupy a special place in nature. Representatives of the plant world are capable of photosynthesis, they convert the energy of sunlight into organic matter and oxygen. They get their food from the soil and their environment, so they don't have to move in search of food. Fertilization is carried out with the help of rodents, insects, wind, so their muscle and nervous tissue is not developed. Unlike animals that travel great distances to obtain food and search for favorable breeding grounds and raising offspring.

Significance in nature and human life

1. Oxygen enrichment of atmospheric air.
2. An integral part of food chains.
3. Used as building material, raw materials for the manufacture of paper, furniture, etc.
4. Application useful properties in medicine.
5. Production of natural fabrics (linen, cotton).
6. Purify the air from dust pollution.

Life cycle

Higher plants are characterized by the presence of a clearly pronounced alternation of two generations: sexual (gametophyte) and asexual (sporophyte). Their sporophyte gradually took a dominant position over the gametophyte. Only bryophytes are an exception, since their gametophyte reaches a greater development, while the sporophyte, on the contrary, is significantly reduced.

In the process of evolution, the sexual process became more complicated, multicellular genital organs developed, which well protect the egg from drying out. The female gamete, the ovum, is immobile. Gradually there were significant changes in the structure and physiology of male germ cells.

Motile, flagellated spermatozoa have become more perfect types higher plants (angiosperms) in sperm without flagella, which have lost the ability to move independently. And if in more ancient terrestrial representatives (mosses, club mosses, horsetails and ferns) there is still a dependence of the act of fertilization on aquatic environment, then in more organized types (most gymnosperms and all angiosperms) there is already complete independence of sexual reproduction from drip-liquid water.

The sporophyte is an asexual diploid generation that produces asexual reproductive organs, the sporangia. In them, after reduction division, haploid spores are formed. They develop into a haploid gametophyte.

Origin

About 400 million years ago, the first forms of plants appeared, adapted to life on land. Leaving the water led to adaptive changes in the structure certain types that needed new structural elements to survive.

So vegetable world left the aquatic environment and began to populate the land. Such "explorers" were rhinophytes, which grew near the shores of reservoirs.

This is a transitional form of life between lower plants (algae) and higher ones. In the structure of rhinophytes, there are many similarities with algae: real stems, leaves, and root system were not traced. They were attached to the soil with the help of rhizoids, through which they received nutrients and water. Rhinophytes had integumentary tissues that protected them from drying out. They reproduced by means of spores.

Rhiniophytes later modified and gave rise to the development of club mosses, horsetails, ferns, which already had stems, leaves, and roots. These were the ancestors of modern spore plants.

Why are mosses and flowering plants classified as higher spores?

Mosses are higher plants that have the most primitive structure. root system missing. They are distinguished from algae by the presence of rhizoids, the body is differentiated into organs and tissues. Mosses, like higher plants, reproduce by spores.

Flower representatives have a body divided into organs. Vegetative organs - a root with an escape, which provide growth and development. As well as reproductive organs - the fruit, seeds, flower, responsible for distribution.

Similarities and differences with algae

Differences:

1. Algae are not differentiated into organs and tissues, often the body is represented by one cell or their cluster. Higher plants are endowed with well-developed tissues, have roots, leaves, stems.
2. In algae, asexual reproduction predominates, by dividing the original mother cell. They also have vegetative and sexual divisions. Higher spore plants are characterized by a strict alternation of sexual and asexual generations.
3. What organelles are absent in cells of higher species, but characteristic of lower species? These are centrioles that are also present in animals.

Similarities:

1. Mode of nutrition - both groups of plants are photoautotrophs.
2. Cell structure: the presence of a cell wall, chlorophyll, nutrients.
3. They cannot actively move, two phases alternate successively in the life cycle: gametophyte and sporophyte.

The appearance of higher plants marked new era the life of the planet. Their occurrence is associated with geological changes in the structure of the continents and the need to adapt to the characteristics of life outside the water.

The diversity of life conditions on Earth contributes to the formation of many forms of existence of living organisms.

Higher plants - definition, structure, characteristics and signs

Multicellular land plants that are able to use light in the process of life, have developed organs and tissues, and are characterized by alternating types of reproduction, are called higher.

Development took place in an effort to adapt to terrestrial existence.

The result was a transformation in the structure:

• roots that absorb water and minerals, and also strengthen the plant in the soil;
• leaves capable of synthesizing organic substances from inorganic ones;
• stems conduct organic matter and water.

Terrestrial plants are characterized by alternation of generations and autotrophic nutrition.

Origin of higher spore plants

The theory says that the ancestors of land plants - streptophyta, were forced to adapt to other living conditions due to geological changes. Importance had the fact that only the fittest algae survived.

Transitional forms developed protective film— cutin deposited on the surface. Film formation in in large numbers prevented gas exchange, causing the plant to die. In organisms, the cutin of which was formed moderately, the epidermis with stomata was formed - a complex tissue that protects against drying out and also does not interfere with gas exchange.

The appearance of the epidermis prevented the absorption of water by the whole body, thereby contributing to the formation of unicellular filaments - rhizoids. The result of the development process was the formation of more complex system- roots.

Illumination on land significantly exceeds the same indicator in water, due to this, the number and size of photosynthetic organs - leaves, have significantly increased. The distribution of substances formed in the process of photosynthesis, and water absorbed by the roots, is carried out by the conducting organ - the stem.

The rapid increase in species, the spread of higher organisms is explained by the development of vegetative organs and changes reproductive system, which, under conditions of terrestrial habitation, must have reliable protection.

The reproductive multicellular organs of terrestrial plants - gametangia and sporangia - have a shell of living cells that protects the spores from drying out.

How do higher plants differ from lower ones?

We list the main ones:

1. The tissues and organs that make up plants have a complex multicellular structure.
2. The habitat is mostly dry land.
3. In the process of development, there is an alternation of generations - gametophyte and sporophyte.
4. The spore is protected by a hard multicellular membrane.

Departments of higher plants

According to the classification, the subkingdom of higher plants includes 9 departments.

Representatives of the first three divisions are completely extinct. The remaining six are living organisms.

Rhyniophytes

The first higher plants that gave rise to other departments are Rhiniophytes or Rhynia. They are characterized by a primitive grassy appearance, reaching a height of 60 cm. They had a simple structure. True leaves and roots were absent, instead of roots there was a rivomoid organ, from which rivoids went down, and stems went up.

Photosynthesis was carried out by a stem branching mainly into two shoots. The sporangia were attached to the axes and spores developed in them.

The presence of integumentary tissues, as well as stomata, indicates that representatives of the department grew on land. Cooksonia is considered the most ancient representative of the department.

Zosterophyllophytes

They have much in common with rhinophytes. Some scientists believe that the Zosterophyllophytes laid the foundation for the Lycopsids. They differ in that they had an upright stem covered with a thick layer of cuticle.

Sporangia collected in spike-like formations have a short stalk, as well as identical spores. The representative is Gosslinglia, it has no roots, and on the stems there are branches with twisted tops.

bryophytes

A feature is the predominance of the haploid phase (sexual generation); the diploid phase is poorly developed. For the sexual process of mosses is required humid environment, therefore, they must grow in low-lying, swampy places, which is facilitated by their small size.

The main differences between bryophytes and other departments:

• weak illumination is sufficient for the formation of organic matter;
• water is absorbed by the whole body;
• ability to grow up on the poor nutrients soils, take a state of suspended animation for a long period. All this ensures competitiveness in comparison with other representatives of departments.

Bryophytes are divided into three classes:

1. Hepatic class. Gametophytes are characterized by a dorsinventral structure. Leaves are always single-layered, rhizoids are single-celled. They grow in the tropics, entangle the soil, trunks, leaves of trees with a continuous carpet. These include Blassia small (Blassia pusilla).
2. Class Anthocerota. At the edges of lamellar rosette-shaped thalli, there are meristematic cells that form lobes that overlap each other and give the thallus a curly appearance. The most common is the genus Anthoceros.
3. Moss class. They are characterized by the presence of leafy shoots of radial symmetry. Rhizoids are located on leaves, stems are always multicellular. Most mosses grow in northern and temperate latitudes. bright representative are sphagnum, their species differ not only in structure, but also in confinement to natural conditions.

Lycopsformes

Herbaceous forms of lycopods can be found at the present time. They have shoots with small leaves, roots.

Leaves represent a whole leaf blade with an expanded base in the form of a pillow. They are divided into two classes - Lycopsoid and Polushnikovye.

psilotoid

Psilotophyta are represented by only one family - Psilotaceae. There are no roots, so they often grow on other trees. They can be found both on soils rich in organic matter and on the rocks of tropical forests. In the process of fertilization, the participation of water is mandatory.

One of the representatives - Psilot naked - an ornamental fern. It got its name from the lack of leaves. Grows at the base of palm trunks or humus soils. Reproduces by spores.

horsetail

The department is divided into two classes - Sphenophyllic and Horsetail.

A prominent representative is field horsetail - perennial herbaceous plant with roots. Serves as an indicator of acidic soils.

The stems are divided into internodes, from which underdeveloped, dark, tooth-like leaves depart. The spores are located in the spore-bearing spikelet. Reproduction takes place at high humidity: rain or heavy dew.

Ferns

Perennial herbaceous, rarely tree plants. They are characterized by macrophyllia - powerfully developed relatively short leaves. Them big leaves(fronds) are solid or strongly dissected, twisted like a snail in a kidney.

In most ferns, leaves perform two functions - photosynthesis and sporulation. Spread all over the globe, but the maximum diversity of species is found in the tropics.

The department has five classes: Cladoxyleaceae, Zygopteridae, Uzhovnikovae, Marattiaceae, Polypodia.

Gymnosperms

Modern biology includes four classes: Cycads, Ginkgos, Conifers and Gnetos. In ancient times, they included two more, already extinct, classes: Seed ferns and Bennettites.

Reproduction of gymnosperms is carried out by seeds - multicellular organs containing the rudiment of the embryo, endosperm and a multi-layered peel. They are the most highly organized department in their morphological features, approaching the department of angiosperms.

Pine Koch (Crimea)

Typical representatives of our country are spruce and pine.

Conclusion

The subkingdom of higher plants has come a long way in the course of its evolution. In the most developed representatives, you can see a flower, a seed, a fruit. All changes in the body took place in order to gain a foothold on land: the appearance of roots, leaves, the improvement of the method of reproduction.

Only higher plants are capable of producing organic matter from inorganic matter.

general characteristics. Higher plants include mosses, club mosses, horsetails, ferns, gymnosperms, angiosperms (flowering). Unlike lower plants, higher plants have well-differentiated tissues and organs. All higher male and female reproductive organs are multicellular. Ontogeny in higher plants is divided into embryonic and postembryonic periods.
Higher plants, according to a very important feature - the structure of the female genital organs - are divided into two large groups: archegonial and pistillate. The first of them includes, for example, the departments Bryophytes, Lycopsids, Horsetails, Ferns, Gymnosperms and unites more than 50 thousand species. All representatives of this group have a female genital organ - archegonium. The second group - pistils, is represented by one department - Angiosperms, or Tsvetkovy (about 250 thousand species), the female genital organ of which is the pistil.
Tissues of higher plants. Tissue is a collection of cells that are similar in morphological and physiological characteristics and perform certain functions. In the process of evolution, the most perfect tissues were formed in flowering plants.
Educational fabrics represented by young, rapidly dividing cells. Localized in the kidneys and the zone of reproduction of the roots. They provide the growth of plant organs in length and thickness, the formation of tissues.
Integumentary tissues(skin, cork, rind) are formed either by living, densely packed cells (skin) covering leaves, green stems and all parts of the flower, or by several layers of dead cells covering thick stems and tree trunks. Protect organs.
Conductive tissues form vessels, sieve tubes and conducting vascular fibrous bundles. Vessels are hollow tubes with woody walls. They form a wood-xylemma that runs along the root, stem and leaf veins. Provide an upward flow of water and minerals. Sieve tubes form a vertical row of living cells with sieve-like transverse partitions. A bast is formed - a phloem located along the root, stem, leaf veins. Carry out the transport of organic substances from the leaves to other organs and tissues. Conductive vascular-fibrous bundles form separate strands (herbs) or a continuous array (woody forms).
mechanical fabrics (fibers) consist of long lignified dead cells located around vascular-fibrous bundles. They act as the backbone of the plant.
Main fabrics subdivided into assimilation and storage. Assimilation tissues are represented by cells that form the columnar and spongy tissue of the leaf. They form the pulp of the leaf and stem, carry out photosynthesis and gas exchange. Storage tissues are formed by cells filled with starch, protein, oil drops, etc.
TO excretory tissues lactic vessels, or lactiferous vessels, whose cells secrete milky juice.