External structure of the leaf. Variety of leaves in shape and size. Topic: External leaf structure

Lesson type - combined

Methods: partially search, problem presentation, reproductive, explanatory and illustrative.

Target:

Students’ awareness of the significance of all the issues discussed, the ability to build their relationships with nature and society on the basis of respect for life, for all living things as a unique and invaluable part of the biosphere;

Tasks:

Educational: show the multiplicity of factors acting on organisms in nature, the relativity of the concept of “harmful and beneficial factors”, the diversity of life on planet Earth and options for adaptation of living beings to the entire range of environmental conditions.

Educational: develop communication skills, the ability to independently obtain knowledge and stimulate one’s cognitive activity; ability to analyze information, highlight the main thing in the material being studied.

Educational:

Formation ecological culture based on recognition of the value of life in all its manifestations and the need for a responsible, careful attitude towards the environment.

Forming an understanding of the value of a healthy and safe lifestyle

Personal:

nurturing Russian civic identity: patriotism, love and respect for the Fatherland, a sense of pride in one’s Motherland;

Formation of a responsible attitude towards learning;

3) Formation of a holistic worldview, corresponding modern level development of science and social practice.

Cognitive: ability to work with various sources of information, transform it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.

Regulatory: the ability to organize independent completion of tasks, evaluate the correctness of work, and reflect on one’s activities.

Communicative: Formation of communicative competence in communication and cooperation with peers, seniors and juniors in the process of educational, socially useful, educational and research, creative and other types of activities.

Planned results

Subject: know the concepts of “habitat”, “ecology”, “ environmental factors“their influence on living organisms, “connections between living and nonliving”;. Be able to define the concept of “biotic factors”; characterize biotic factors, give examples.

Personal: make judgments, search and select information; analyze connections, compare, find an answer to problematic issue

Metasubject:.

The ability to independently plan ways to achieve goals, including alternative ones, to consciously choose the most effective ways to solve educational and cognitive problems.

Formation of semantic reading skills.

Form of organization educational activities - individual, group

Teaching methods: visual-illustrative, explanatory-illustrative, partially search, independent work with additional literature and textbook, with COR.

Techniques: analysis, synthesis, inference, translation of information from one type to another, generalization.

Goals: introduce the variety of leaves and the features of their external structure; teach to recognize leaves by types of venation, shape of the leaf blade, shape of the edge, location on the stem, distinguish between simple and compound leaves.

Equipment and materials: indoor plants, herbariums of plants with various types leaf blades, willow leaf herbarium (for each desk).

Key words and concepts: leaf, leaf structure, leaf blade, petiole, leaf base, stipules; methods of leaf attachment: petiole leaf, sessile leaf, moisture leaf; simple and compound leaves; dissected leaves: palmately lobed, palmately dissected, palmately divided, pinnately lobed, trifoliate; leaf edge shapes: entire, serrated, serrate, spinous (spinate), crenate, pitted, sinuous; shapes of leaf blades: oval, ovoid, lance-shaped, sagittal, pinnately lobed, pinnately dissected, paripirnately compound, odd pinnately compound, linear, trifoliate, palmate

Teacher's story with elements of conversation

Leaf blades can be classified according to form. There are a huge number of forms of leaf blades: round, ovoid, linear, lanceolate, spear-shaped, sagittal, heart-shaped, oblong etc. Can also be classified according to edge shape. In addition to leaves with a solid edge (they are called - whole-edged), There are several main types of edge shapes: serrated, serrated, spiny (spiny-toothed), crenate, pitted, winding.

It should be noted that leaves may be found on one shoot various shapes, size, color. This phenomenon is called heterophilia. Heterophily is characteristic of buttercup, arrowhead and many other plants.

If you look at the leaf blade, you will notice veins- bundles of conducting vessels. You've seen them on a willow leaf. The arrangement of veins on the leaf may vary. The method of placing the veins is called venation. There are several types of venation: parallel, arc, dichotomous, mesh (finger And feathery).

Parallel, or arc, veining is characteristic of monocotyledons, and reticulate veining is characteristic of dicotyledons.

Remember which plants are dicotyledonous.

What other signs of dicotyledonous plants do you know?

Give examples of monocotyledonous and dicotyledonous plants.

Consolidation of knowledge and skills Practical work 13. DEFINITION OF SIMPLE AND COMPLEX LEAVES

Work progress

Describe the herbarium specimens of leaves lying on your tables according to plan.

Plan

What is the method of attaching this leaf to the stem?

What is the veining of the leaf?

Is this a simple sheet or a complex one?

What is the shape of the leaf blade of this leaf?

What is the shape of the leaf edge?

2.Which plant - monocot or dicot - does this leaf belong to?

3. Look at the drawing. Write down the types of venation that the leaves shown in the picture have.

Leaf venation

4. Leaves simple and compound, their venation and leaf arrangement

Consider the proposed plant samples. Give a brief description of their leaves according to the plan, name of the plant, simple or complex leaves, type of venation, type of leaf arrangement.

Creative task. Make an impression of the sheet. To do this, you will need a dried leaf (the leaves are dried in several layers of newspaper under pressure), gouache or watercolor paints, watercolor paper, a small paint roller. The sheet should be thickly smeared with watercolor or gouache paint and place it on watercolor paper. Cover the top with blotting paper and roll with a roller. Make a composition from prints of various leaves.

An activity for students interested in biology. Using additional literature, select examples of plants with different types of leaf blades.

Manifoldleaves

Sheet. Speciesleaves. Issue#2

Resources:

I.N. Ponomareva, O.A. Kornilov, V.S. Kuchmenko Biology: 6th grade: textbook for students of general education institutions

Serebryakova T.I.., Elenevsky A. G., Gulenkova M. A. et al. Biology. Plants, Bacteria, Fungi, Lichens. Trial textbook for grades 6-7 high school

N.V. Preobrazhenskaya Biology workbook for the textbook by V. Pasechnik “Biology 6th grade. Bacteria, fungi, plants"

V.V. Pasechnik. Teacher's Guide educational institutions Biology lessons. 5-6 grades

Kalinina A.A. Lesson developments in biology grade 6

Vakhrushev A.A., Rodygina O.A., Lovyagin S.N. Verification and tests To

textbook "Biology", 6th grade

Presentation hosting

In the proposed lesson " External structure leaf. Diversity of leaves”, built in an interactive mode, demonstrates methods of developing educational and information skills that ensure the discovery, processing and use various types information and educational and logical skills, providing a clear structure of the content of the formulation and solution process educational tasks(analysis and synthesis, comparison, generalization and classification, etc.) .

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MUNICIPAL EDUCATIONAL INSTITUTION

SECONDARY SCHOOL No. 1 st. OLGINSKAYA

Biology lesson

External structure of the leaf.

Variety of leaves.

Biology teacher

Municipal educational institution secondary school No. 1 st. Olginskaya

Sushchenkova I.A.

ID - 233-231-924

2011

Methodical guide for the lesson

Item: Biology, 6th grade

Lesson topic: External structure of the leaf. Variety of leaves.

Didactic goals:
Formation of information competence: in the field of independent cognitive activity; critical thinking, skills of independent work with information;develop the ability to analyze, highlight the main thing, classify, generalize, prove; establish analogies and cause-and-effect relationships; contribute to the formation of divergent thinking and reflective skills of students.

Methodological goals:

To introduce students to the variety of leaves and the features of their external structure;
To teach to recognize leaves by types of venation, the shape of the leaf blade, the shape of the edge, location on the stem, to distinguish between simple and complex leaves;
Test your ability to apply acquired theoretical knowledge in practice, draw conclusions and generalizations.

Educational tasks

Formation of communicative and cooperative competencies

Form of organization of educational activities. Work in small groups. Laboratory work"External leaf structure"

Equipment: indoor plants, herbariums of plants with different types of leaf blades, drawings and photographs of leaves.

Key words and concepts: leaf, leaf structure: leaf blade, petiole, leaf base, stipules.Methods for attaching leaves: petiolate leaf, sessile leaf, vaginal leaf.Simple and compound leaves.Dissected leaves: palmately lobed, palmately dissected, palmately divided, pinnately lobed, trifoliate.Leaf edge shape:entire-edged, jagged, serrate, spinous (thorn-toothed), crenate, notched, sinuous.Shapes of leaf blades: oval, ovoid, spear-shaped, sagittal, pinnately, pinnately dissected, paripirnately complex, imparipinnately complex.Leaf venation: parallel, arcuate, reticulate, palmate, pinnate.

Lesson progress

Organizational moment.

The class is divided into 3 groups of students sitting at separate round tables.

Stage I. Updating knowledge about the studied organs of a flowering plant

Work technology: independent work of students for 3-4 minutes and subsequent group discussion

1 group.

Fill in the missing words. Title the text. Continue the story, illustrating it with diagrams and drawings.

... is the main above-ground organ of the plant. It consists of…. with…….and……. located on it. . The section of the stem on which the leaf develops is called….., and the distance between two nodes…… The angle between the leaf and the internode located above is called….. . The way leaves are arranged on a stem is called leaf arrangement. Leaf arrangement can be……..

Assignments contribute to the development of skills to work with information presented in the form of incomplete text, analyze it, supplement it, highlight the main thing; draw up illustration diagrams.

2nd group

Create a system of concepts from the proposed terms.

Generative organs; stem, flowers, shoot, root, vegetative organs, organs, fruits, leaves, seeds, buds.

The tasks contribute to the formation of skills: analyze the proposed objects and establish their spatial relationships, creating a system of concepts, expand and collapse information

3 group

Compare picking and pinching plants. What do these procedures have in common? The meaning of procedures.

Assignments contribute to the formation of skills to analyze and compare (aboutdefine the aspect of comparison and conduct an incomplete single-linear comparison), prove a point of view.

Stage II. Learning a new topic

Black box.

Teacher. The subject of our study is in a black box. You are invited to determine what it is, for this I will sequentially pronounce the statements, and you will explain whether this information is sufficient for precise definition object(technique of working with insufficient information).

The box contains the plant organ.
This vegetative organ.
It occupies a lateral position in the shoot, is located at the nodes of the stem and usually has a flat shape.

Lesson topic sheet.

What do we already know about this organ?

In groups, let's create a syncwine for the concept of “leaf” and try to incorporate into it the knowledge we already have about this vegetative organ.

(the rules for compiling a syncwine are written on the board)

There are 5 lines in syncwine:

1 – concept (word);

2 – adjectives (two words);

3 – verbs (three words);

4 – sentence (of four words);

5 – noun (one word).

Adjectives and verbs must reveal concepts, and the sentence must have a semantic character.

Listening to syncwines and discussing them. This task contributes to the formation of the skills to highlight the main thing, generalize and establish analogies.

Let's look at the external structure of the leaf.

Let's sketch it in a notebook and sign its main parts (working with illustrations in a book)

The shape, size, and structure of leaves can vary greatly. In order to understand such a variety of leaves, they need to be classified.

Remember what classification is?

But the external variety of leaves is so great that it is impossible to create unified system classification of leaves according to one or more characteristics. Therefore, there are several different classifications of leaves based on various characteristics.

Compare the suggested leaves(the pictures are attached to the board) and name the signs by which they differ. Based on these characteristics, we will create various classifications of leaves.Students' answers are written on the board.

(Development of skills to analyze, compare)

– Number of leaf blades

– Presence or absence of petiole

– Types of venation

– Shape of leaf blades

– Sheet edge shape

Groups receive tasks - a sign for classification, herbarium specimens, images of plants. They work with the textbook text, transform it into a diagram, and illustrate it with examples (analysis and synthesis of information).

1 group

Simple and compound leaves

Characteristic – number of leaf blades

2nd group

Sign – way of veins occurrence

Leaf venation

3 group

Attaching leaves to stem.

Sign - ways of attaching leaves to the stem

Group performances, filling out diagrams in workbooks

III. Consolidation of knowledge

Lab 8

Topic: External structure of a leaf.

Purpose: Study of the external structure of simple and complex leaves.

Equipment

Indoor plants: pelargonium, tradescantia.
Herbarium of leaves of rose hips, rowan, oak, lilac.

Work progress

Look at the green leaves indoor plants- pelargoniums and tradescantia. Find the parts of the leaf. Draw them in your notebook and label them.
Examine the veins on the leaf blade of pelargonium. Compare them with the veins of a Tradescantia leaf. Note how they differ. Draw and label the type of venation. Which plants, monocots or dicotyledons, have leaves?
Note how the leaf is attached to the stem.
Examine the leaves in the herbarium different plants. Find simple and compound leaves among them.
Record the results in the table:

Individual work(may be offered as homework)

When using the words therefore, because, therefore, since, add the beginning or end of each sentence.Independent work of students.Then – a collective discussion of the results.Students should pay attention to the fact that there are no clearly correct answers here, since almost all of these sentences may have different options start or end.

…………leaf vegetative organ……..
…………the leaf occupies a lateral position in the shoot………………..
…………leaf cells contain chloroplasts…………………..
…………leaf is capable of movement…………………
This task helps develop the ability to establish cause-and-effect relationships.

My mental activity during the lesson was……….
What I liked most was……………………….
I haven’t quite succeeded yet…………………….
Today's lesson showed me………………………

The task is aimed at developing students’ reflective skills and contributes to the formation of adequate self-esteem.

Homework

This is a task with freedom of choice and freedom of action. Each student has the right to choose from a number of proposed tasks:

make a drawing for the topic;
create a diagram of the supporting outline;

write a cheat sheet for the lesson;

People are used to calling a wide green plate a leaf. However, the external structure of the leaf is more complex. Let's consider the variety of shapes, location on the stem, and leaf venation.

Leaf parts

A leaf is a lateral organ of a shoot, emerging from a bud and attached to the stem using a petiole. The table “Characteristics of the external structure of leaves” describes each part in more detail.

*Leaf parts*	*Definition*	*Characteristic*
Leaf blade	The main, widest part of the leaf	Has limited growth; Has bilateral symmetry; Lives for one growing season; Conifers live up to 5-15 years; Tropical plants grow up to 15 m in length (usual size is up to 10 cm)
	The narrow part of a leaf connecting the leaf blade to the stem	Turning, orients the sheet towards the light; Softens impacts (raindrops, insect landings)
Base	Sheet attachment location	Holds the leaf on the stem
Stipules	Outgrowths at the base in the form of scales, small leaves, spines	They form a bud and protect the future leaf; They fall off after the buds open; In some cases, they are saved and play the role of a leaf

Leaves with petioles are called petiolate. In the absence of a petiole, the leaf blade grows from the stem. Such leaves are called sessile. Example - flax, wheat, dandelion.

Simple and complex

All leaves are divided into two types:

simple - the leaf has one leaf blade;
complex - consist of several leaves attached to a common petiole.

in autumn simple leaves fall off completely along with the petiole. Example - birch, elm, aspen. The compound leaves disintegrate into leaflets, and the common petiole is separated from the shoot. Examples are rowan, clover, rosehip.

Based on their location on the common petiole, compound leaves are divided into three types:

pinnately - the leaves lie on the sides of the petiole; are divided into paripirnate - even number, each leaflet has a pair, and the odd-pinnate ones have an odd number, ending in one leaf;
palmate compound - leaves extend from the top of the petiole in different directions;
trifoliate - consist of three leaves.

The most complex leaves are double or triple pinnate or palmate. In these cases, the common petiole has branches.

Variety of shapes

The leaves differ in the shape of the leaf blade. Leaves are:

rounded;
oval;
needle-shaped;
lanceolate;
heart-shaped;
ovoid;
linear;
sickle-shaped;
fan-shaped;
etc.

Rice. 1. Different leaf shapes.

The edges of the leaves are also varied. Highlight:

entire (smooth);
toothed;
double-toothed;
serrated;
crenate;
wavy;
spiny;
notched.

Depending on the depth of the excavation, the leaves are divided into three types:

solid - depth less than a quarter 1/2 sheet (birch);
dismembered - the recess does not reach the axis (oak);
dissected - the notch reaches the center (potatoes).

Leaves can be arranged differently on the petiole. There are four types of location:

next - one leaf per node one after another (apple tree);
opposite - two leaves per knot in both directions (mint);
whorled - three or more leaves from one node (oleander);
rosette - in a circle at the same height (agave).

Rice. 2. Leaf arrangement.

Venation

Any plate, regardless of its shape and complexity of structure, has internal network veins that conduct nutrients to leaf cells. The veins also serve as a kind of skeleton - they hold their shape and give the leaf strength. Venation is of three types.

Mesh . The main veins branch into smaller ones. The structure resembles a network. Reticulate venation is divided into three types - pinnate (apple), radial (ceanothus), palmate (maple). Typical for dicotyledonous plants.
Parallel . The veins run parallel from the base to the top of the leaf. Found in monocotyledonous plants.
Dugovoe . Resembles parallel, but the veins follow the round shape of the leaf, starting from the base and connecting at the apex. Example - plantain, lily of the valley. Typical for monocots.

Rice. 3. Types of venation.

What have we learned?

From a 6th grade biology article we learned about components, diversity and shapes of plant leaves. Leaves can be simple or complex, rounded or elongated, with different edges, location on the shoot, and type of venation.

Test on the topic

Evaluation of the report

Average rating: 4. Total ratings received: 692.

The root is the main organ of plants, which performs the most important functions: anchoring in the soil, conducting and storing water and minerals dissolved in it. All plants need to perform these tasks, but not to the same extent. That is why there is a huge variety of root systems.

Root systems are divided into two groups:

Tap root system: there is a main root, from which lateral roots spread throughout the soil (dicots);
Fibrous root system: the main root cannot be distinguished, all roots are the same (monocots).

Depending on the habitat, plants have different root lengths. Desert plants have extremely long roots to extract moisture from deep groundwater. Because of permafrost, tundra plants have to keep their roots near the surface. This length of roots cannot provide adequate nutrition, so the plant grows small to save nutrients.

The metamorphoses of the roots do not end there. Some plants went further and came up with bizarre forms, which were called root modifications.

Root modifications:

Variety of leaves

A leaf is a plant organ that is responsible for photosynthesis and water evaporation (transpiration). Plants have different nutrient and water needs, which is why there is a variety of leaves.

According to their external structure, the leaves are:

Petiolate: leaves are connected to the stem using a petiole (oak, birch);
Sessile: leaves attached to the stem at the base of the leaf blade (aloe, wheat).

Variety of leaves by external structure:

The leaves differ in veining:

Reticulate venation: small veins extend from the large vein, forming a whole network; reticular, in turn, is divided into pinnate and palmate (cherry, pear, apple);
Parallel venation: the veins are arranged in parallel (wheatgrass, cereals);
Arc venation: the veins are arranged in an arc (plantain, lily of the valley, tulip).

Leaf venation:

Depending on the habitat and soil moisture, plants have different leaf shapes. If the plant lives in a humid area, it will have large leaves with a huge number of stomata. Such a plant does not save moisture and is not afraid of getting an extra portion. sunlight. If the plant lives in a dry area, it will have narrow leaves with few stomata. Often such plants have additional protection from loss of moisture: waxy coating and thick cuticle.

Radical modifications of parts of the plant did not spare the leaves.

Thorns. This modification can have two purposes: either the plant greatly reduces its surface in order to slow down the evaporation of water (cactus), or it protects itself from herbivores (barberry).
Water storage sheets. Plants of arid habitats (aloe) have such modified leaves. With their help, the plant retains the necessary moisture.
Mustache. With the help of such leaves, plants are attached to a support (peas). Do not confuse with sucker roots and trailing roots: although the function is the same, the origin is different. Antennae develop from former leaves, and sucker roots and trailing roots are made from roots.
Leaves carnivorous plants . Carnivorous plants live on poor soils, so they have adapted to extreme conditions in an extreme way (Venus flytrap). On the surface of such leaves there are special glands that secrete digestive enzymes (pepsin) and organic acids (formic acid). If an insect lands on the trapping organ of such a plant, its secretion (excretion) of digestive substances increases. Glandular hairs bend towards the insect (sundew) or bend the edges of the leaf on which the insect is located (butterfly). After capturing the prey, enzymes begin to work actively and break down insects into simple substances that the plants themselves can use. Thus, the leaves of insectivorous plants are able to digest insects, thereby replenishing the supply of nutrients.

Leaf modifications:

Variety of stems

The stem of a plant is a part of the shoot that performs a number of important functions: conducting and storing substances, protecting, providing vegetative propagation, attachment to a support. To provide all functions, necessary for the plant, there are a variety of stem types.

Diversity of stems by degree of lignification:

Variety of stems according to cross-sectional shape:

In direction of growth:

Erect: for this type of stem the plant must have mechanical tissue (birch);
Climbing: such plants are capable of twining around a support (convolvulus);
Climbers: use modified organs (grapes) to attach to a support;
Recumbent: lie on the ground (loosestrife);
Crawling: also lie on the ground, but can take root (strawberry).

Variety of stems according to growth direction:

Depending on the above characteristics of the stem, life forms of plants are distinguished:

Tree: a plant with a woody stem that has a main trunk (birch);
Shrub: a plant with a woody stem that does not have a main trunk when mature, that is, when the plant has reached its peak of development (lilac);
Shrub: low growing plant, which does not have a main trunk when mature (blueberry);
Herbaceous plant: annual, biennial or perennial with a grassy stem (clover).

Life forms of plants:

Variety of shoots

A shoot is a terrestrial vegetative organ of a plant, which is a stem with leaves and buds. The shoots of some plants have changed so much that they can easily be confused with other parts, for example, with the root. Only maximum concentration will help in this difficult task.

Modifications of shoots:

Tubers. The potato fruit is actually a modified shoot called a tuber. The underground shoots of potatoes are called stolons, and the tuber is its thickening. On the surface of the potato tuber, especially at the top, there are buds - eyes. Such a total modification of the shoot is necessary for a large deposition of nutrients, in particular starch.
Bulbs. Such modifications can be seen directly in the onion or tulip. If you cut an onion, you can see its parts: the bottom and scales. The bottom is located in the lower part and is a residual flat stem. Above it are modified leaves - scales. This modification serves to accumulate water and nutrients in the juicy internal scales.
Rhizomes. The rhizome of the plant is easily confused with the root, but it is a modified shoot, as it has buds on its surface. Thanks to this, both adventitious roots and new shoots can grow from the rhizome. In practice, propagation by rhizomes is used: from a section of rhizome placed in the soil, an independent plant grows. Many plants have this modification, for example, nettle and lily of the valley.
Spikes. Reducing the surface of the stem serves to reduce evaporation and protection from herbivores (acacia).
Mustache. The tendrils allow strawberries to reproduce vegetatively and spread over various distances.
Storage shoots. Based on the name, such shoots perform the function of storing water and nutrients (cactus, orchids).

Modifications of shoots:

Variety of flowers

A flower is a plant organ that is intended for sexual reproduction. Despite the fact that the flower performs only one function, diversity has not spared this part of the plant.

By perianth type:

Types of perianth:

By different shapes flowers:

Regular and irregular flowers:

Dioecious and bisexual flowers:

A flower formula is used to describe a variety of flowers. To use it, you need to remember the parts of the flower.

The flower formula includes the following abbreviations:

O - simple perianth;
Ch - sepals;
L - petals;
T - stamens;
P - pestle;
∞ - if the number is greater than 12;
*— the right flower;
- wrong flower;
♀ — same-sex female;
♂ - same-sex male.

For example, the formula of a staminate flower of a cucumber will be presented as follows: ♂*H(5)L(5)T(5)P0, that is, it is a regular unisexual male flower with five fused sepals, five fused petals, five fused stamens, without a pistil. If the number is not enclosed in brackets, then this part of the plant does not grow together.

Variety of inflorescences

An inflorescence is several flowers connected to each other. With the help of the appearance of inflorescences, plants increase the likelihood of pollination by insects: from a long distance the inflorescences are visible better.

The variety of inflorescences is great:

Simple inflorescences: such inflorescences have flowers (plantain) on the main axis (the main pronounced shoot);
Complex inflorescences: in such inflorescences, other simple inflorescences (lilac) sit on the main axis;
Naked inflorescences: in such inflorescences, the bracts (leaves on the stalk at the very base of the flower) are reduced or absent altogether (shepherd's purse);
Leafy inflorescences: in such inflorescences the bracts are highly developed (violet).

Simple and complex inflorescences:

In turn, simple inflorescences are divided into:

Raceme: on the long axis there are pedicels, at the ends of which there are flowers (cabbage);
Simple spike: sessile flowers (plantain) are located on the long axis;
Ear: on a long thick axis there are sessile flowers (corn);
Simple umbrella: long pedicels (primula) emerge from the apex of the axis;
Scutellum: pedicels are located on the long axis, with the lower ones being much longer than the upper ones (pear);
Head: sessile flowers (clover) are located on a shortened axis;
Basket: sessile flowers (sunflower) are located on the extended axis.

Simple inflorescences:

And complex inflorescences are like this:

Panicle (complex brush): brushes (lilac) are located on the axis;
Complex spike: spikelets (wheat) are located on the axis;
Complex umbrella: umbrellas (parsley) are located on the axis;
Monochasium: on an unexpressed axis there is one axis of the second and third order;
Dichasia: on the unexpressed axis there are two axes of the second and third order;
Pleochasium: on the inexpressible axis there are more than two axes of the second and third order.

Complex inflorescences:

Variety of fruits

A fruit is an organ of a plant that contains seeds for further dissemination. Parts of the fruit: pericarp and seed. The pericarp (pulp) protects valuable seeds from unfavorable environmental conditions.

Classification of fruits by complexity:

Simple (true) fruit: develops from a flower that has one pistil (pea);
Composite fruit: develops from a flower that has several pistils (raspberry);
Infructescence: develops from a whole inflorescence (pineapple).

Variety of fruits by complexity:

By number of seeds:

Single-seeded fruits (nut);
Polyspermous fruits (apple tree).

By consistency:

Depending on the structure of the fruit, varieties are distinguished:

Berry-shaped fruits. These fruits have a juicy pericarp with many seeds inside.

Berry: no doubt everyone has tried berries; these juicy fruits are covered with thin skin (cranberries, blueberries);
Apple: Surprisingly, not only the apple tree has an apple; an apple is called an apple - a false fruit, the formation of which involves an overgrown receptacle (apple tree, hawthorn);
Bitter orange: citrus fruit (lemon, tangerine).

Berry fruits:

Drupe-like fruits. These fruits have a juicy pericarp and hard seeds (one or more).

Drupe: a juicy fruit with a lignified center of the pericarp - a stone (cherry, apricot);
Polydrupe: a group of drupes formed from a single flower (raspberry, blackberry).

Drupe-like fruits:

Nut-like fruits. These indehiscent fruits have a dry pericarp and a single seed.

Nut: This fruit has a woody pericarp ( walnut, hazelnut);
Nut: small nut (buckwheat, hemp);
Multi-nut: several nuts are located on an overgrown receptacle (strawberry);
Acorn: a fruit with a plus, a cup-shaped organ similar to a saucer (oak);
Achen: This variety of fruit has a leathery pericarp that is not fused to the seed (sunflower);
Caryopsis: unlike the achene, the membranous pericarp of the caryopsis fuses with the seed (wheat, corn).

Nut-like fruits:

Box-shaped fruits. These dehiscent fruits have a dry pericarp and many seeds.

Box-shaped fruits:

Because of this diversity of seeds and fruits, plants have evolved many strategies for dispersing seeds over long distances. Fruits and seeds can be moved by water, wind, animals, and self-propagation.

Hydrochoria - propagation by water. This is how seeds move aquatic plants(water lily, egg capsule). For this plant, they came up with special devices - water bubbles that prevent them from sinking to the bottom. Thus, currents carry seeds over long distances.
Anemochory - dispersal by wind. This is how dry and light fruits and seeds (ash, maple) move. To do this, plants form bizarre outgrowths or tufts that facilitate movement by wind currents.
Zoochory - distribution by animals. In order for the plant to move with the help of animals, you can take two paths: either come up with special outgrowths, or have a succulent pericarp. If a plant has hooks and spines, then it is able to cling to the skin of an animal and thus travel a long distance (burdock). If the plant has a juicy pericarp, then with a high probability a bird will feast on it, digest it and throw away the seed intact (blueberry). The dispersal of seeds by birds is called ornitochory.
Anthropochory is spread by humans. Seeds may become attached to bags when transporting goods (plantain).
Autochory - distribution by self-dispersal. This is how opening fruits (peas, beans) move. With this method, the distance over which the seeds spread is small.

Textile

Where is it located?

Features of cell structure

Meaning

educational

Tops of stems
Root tips
Cambium
Wound

Small dividing cells without vacuoles

Plant growth

Pokrovnaya

Epidermis (skin)
Cork
Bark

Living and dead cells with thick and durable membranes, tightly adjacent to each other

Protection from adverse influences

Mechanical

Lub
Wood

Thick woody shells

Support for plant organs

Conductive

Vessels of wood
Bast sieve tubes

Sieve tubes

Distribution of substances entering the roots and formed in the leaves throughout the body

Main

Leaf pulp
stem core
Root

Chloroplasts in cells

Nutrient formation and accumulation

excretory

Sunbirds
Glands

Selection essential oils, water, nectar

Cell – the basic structural and functional unit of living things, the smallest living system.
Textile - a group of cells that are similar in structure and perform the same functions.

Conductive fabrics ensure the movement of water and nutrients dissolved in it throughout the plant. There are two types of conductive tissue - xylem (wood) and phloem (bast).

Xylem is the main water-conducting tissue of higher vascular plants, ensuring the movement of water with minerals dissolved in it from the roots to the leaves and other parts of the plant (ascending current). It also performs a supporting function. The xylem consists of tracheids and tracheae (vessels) (Fig. 8.3), wood parenchyma and mechanical tissue.

Tracheids They are narrow, highly elongated dead cells with pointed ends and lignified membranes. The penetration of solutions from one tracheid into another occurs by filtration through pores - recesses covered with a membrane. Liquid flows through the tracheids slowly, since the pore membrane prevents the movement of water. Tracheids are found in everyone higher plants, and in most horsetails, mosses, ferns and gymnosperms they serve as the only conducting element of the xylem. U angiosperms Along with tracheids there are vessels.

Figure 8.3. Elements of xylem (a) and phloem (6): 1-5 - ringed, spiral, scalariform and porous (4, 5) trachea, respectively; 6 - ringed and porous tracheids; 7 - sieve tube with companion cell.

Trachea (vessels) - these are hollow tubes consisting of individual segments located one above the other. In the segments on the transverse walls are formed through holes- perforations, or these walls are completely destroyed, due to which the speed of flow of solutions through the vessels increases many times over. The shells of the vessels are impregnated with lignin and give the stem additional strength. Depending on the nature of the thickening of the membranes, tracheas are distinguished as ringed, spiral, scalariform, etc. (see Fig. 8.3).

Phloem conducts organic matter, synthesized in the leaves, to all plant organs (downward current). Like xylem, it is a complex tissue and consists of sieve tubes with companion cells (see Fig. 8.3), parenchyma and mechanical tissue. Sieve tubes are formed by living cells located one above the other. Their transverse walls are pierced with small holes, forming a kind of sieve. The cells of the sieve tubes are devoid of nuclei, but contain cytoplasm in the central part, strands of which pass through through holes in the transverse partitions into neighboring cells. Sieve tubes, like vessels, stretch along the entire length of the plant. Companion cells are connected to the segments of the sieve tubes by numerous plasmodesmata and, apparently, perform some of the functions lost by the sieve tubes (enzyme synthesis, ATP formation).

Xylem and phloem are in close interaction with each other and form special complex groups- conductive bundles.

Mechanical fabrics ensure the strength of plant organs. They form a frame that supports all plant organs, resisting their fracture, compression, and rupture. The main characteristics of the structure of mechanical tissues, ensuring their strength and elasticity, are the powerful thickening and lignification of their membranes, close closure between cells, and the absence of perforations in the cell walls.

Mechanical tissues are most developed in the stem, where they are represented by bast and wood fibers. In roots, mechanical tissue is concentrated in the center of the organ.

Depending on the shape of the cells, their structure, physiological state and the method of thickening of the cell membranes, two types of mechanical tissue are distinguished: collenchyma and sclerenchyma (Fig. 8.4).

Rice. 8.4. Mechanical fabrics: a - angular collenchyma; 6 - sclerenchyma; V -- sclereids from cherry plum fruits: 1 - cytoplasm, 2 - thickened cell wall, 3 - pore tubules.

Collenchyma is represented by living parenchyma cells with unevenly thickened membranes, making them especially well adapted for strengthening young growing organs. Being primary, collenchyma cells easily stretch and practically do not interfere with the elongation of the part of the plant in which they are located. Collenchyma is usually located in separate strands or a continuous cylinder under the epidermis of the young stem and leaf petioles, and also borders the veins in dicotyledonous leaves. Sometimes collenchyma contains chloroplasts.

Sclerenchyma consists of elongated cells with evenly thickened, often lignified membranes, the contents of which die off early stages. The membranes of sclerenchyma cells have high strength, close to the strength of steel. This tissue is widely represented in the vegetative organs of land plants and forms their axial support.

There are two types of sclerenchyma cells: fibers and sclereids.Fibers - these are long thin cells, usually collected in strands or bundles (for example, bast or wood fibers).Sclereids - these are round, dead cells with very thick, lignified membranes. They form the seed coat, nut shells, seeds of cherries, plums, and apricots; they give the flesh of pears their characteristic coarse character.

Main fabric, or parenchyma , consists of living, usually thin-walled cells that form the basis of organs (hence the name tissue). It houses mechanical, conductive and other permanent tissues. The main tissue performs a number of functions, and therefore they distinguish between assimilation (chlorenchyma), storage, pneumatic (aerenchyma) and aquiferous parenchyma (Fig. 8.5).

Figure 8.5. Parenchymal tissues: 1-3 - chlorophyll-bearing (columnar, spongy and folded, respectively); 4-storage (cells with starch grains); 5 - pneumatic, or aerenchyma.

Cellsassimilation T Kani contain chloroplasts and perform the function of photosynthesis. The bulk of this tissue is concentrated in the leaves, a smaller part in young green stems.

In cellshoarding th proteins, carbohydrates and other substances are deposited in the parenchyma. It is well developed in the stems woody plants, in roots, tubers, bulbs, fruits and seeds. Plants of desert habitats (cacti) and salt marshes haveaquifer parenchyma, which serves to accumulate water (for example, large specimens of cacti from the genus Carnegia contain up to 2-3 thousand liters of water in their tissues). Aquatic and marsh plants develop a special type of basic tissue -pneumatic parenchyma, oraerenchyma. Aerenchyma cells form large air-bearing intercellular spaces, through which air is delivered to those parts of the plant whose connection with the atmosphere is difficult

PLANT ORGANS

ORGAN – This is a part of a plant that has a specific location, as well as a characteristic shape and structure, and performs a specific function.

ROOT - axial underground vegetative organ.

Absorption and transport of water and dissolved mineral salts

Vegetative propagation

Release of metabolic products into the soil

Nutrient storage

Synthesis biologically active substances

Fixation in the soil

ROOT FUNCTIONS

ROOT ZONES

ROOT ZONES AND SIGNIFICANCE

Protects the root tip from mechanical damage and ensures root advancement in the soil.

Cells are actively dividing, root meristem. All root tissues are formed from this zone.

The presence of root hairs ensures that the roots absorb water and minerals dissolved in it.

An intermediary between the root absorption zone and the above-ground part of the plant, located above the root hairs. Conducting vessels and lateral roots are formed in this zone.

TYPES OF ROOTS

TYPES OF ROOT SYSTEMS

1- main root

corn

Adventitious roots

Lateral roots

All orchids

MODIFICATIONS OF ROOTS

Swamp cypress, all swamps

Carrots beets

Dahlia, clear

Escape – This is the above-ground part of the plant, consisting of a stem and leaves and buds on it.

Stem – axial aboveground vegetative organ of a plant. The shoot often performs the function of storing nutrients, vegetative propagation of plants and protecting them from being eaten. In such cases it is modified.

ESCAPE BUILDING

MODIFICATIONS OF SHOOTS

Reminds me of a root. It has underdeveloped scaly leaves and buds, and adventitious roots grow from the nodes. Nutrients are stored in the rhizome as a reserve of nutrients. Most often, the rhizome is found in perennial grasses.

Examples: wheatgrass, valerian, lily of the valley, streptocarpus.

Rhizome

An underground shoot on which buds are located in the eyes. Tubers are either underground or aboveground. Tubers serve for plant propagation, store nutrients and withstand unfavorable periods of the year. Under favorable conditions, tubers germinate easily and, thanks to the stored substances, produce started young independent plants.

Example: potatoes, kohlrabi, gloxinia.

Tuber

Calla Tubers

Dahlia Tubers

Potato tubers

It has a shortened stem surrounded by succulent leaves, in the axils of which there are buds. Nutrients are contained in the leaves. Bulbs help plants survive unfavorable conditions and are organs of vegetative reproduction.

Example: onion, tulip, daffodil, hyacinth, hipeastrum, amaryllis.

Narcissus bulb

3. Bulb

spines

They are located in the axils of the leaves and protect the plant from being eaten by animals.

Example: hawthorn, rose, thorn, wild apple tree, cactus.

Mustache

Thin, creeping stems with elongated internodes. They take root at the nodes and give rise to new plants.

Example: strawberry, wild strawberry.

Mustache

Curly shoots that, twining around various supports, support the stem in a certain position.

STEM

Stem (in trees - trunk, branches and shoots) serves as a link between the roots, through which water and minerals enter the plant and leaves, in which nutrients are synthesized.

FUNCTIONS:

Connects all parts of the plant

Nutrient supply

Vegetative propagation

Provides water transport of mineral and organic substances

Forms and bears buds and leaves

TYPES OF STEMES ACCORDING TO THE PRESENCE OF WOOD

Herbaceous

Woody

TYPES OF STEM ACCORDING TO PLACEMENT IN SPACE

climbing plants: field birch, bindweed

Erect plants: all plants with an erect stem: dandelion, clover, chamomile, etc.

Clinging plants Chin, grapes, cucumber, pumpkin, zucchini, melon.

Creeping: strawberries, strawberries.

INTERNAL STRUCTURE OF THE STEM

SHEET

Sheet - lateral organ of a plant.
Functions– photosynthesis, gas exchange, transpiration.

LEAVES

Complex- consisting of several leaf blades: strawberry - trifoliate, rowan - odd pinnate, yellow acacia - pair pinnate.

Simple– consisting of one leaf plate: Linden, cherry, apricot, cereals.

Rice. 3.simple leaves : 1 - needle-shaped; 2 - linear; 3 - oblong; 4 - lanceolate; 5 - oval; 6 - rounded; 7 - ovoid; 8 - obovate; 9 - rhombic; 10 - spatulate; 11 - heart-ovate; 12 - kidney-shaped; 13 - swept; 14 - spear-shaped : 1 - pinnately complex; 2, 3 - trifoliate; 4 - finger-complex.

VENATION –

Leaf fall – this is the shedding of leaves from perennial trees and shrubs; a natural physiological phenomenon.

The meaning of leaf fall

Healthy for the plant and protection against excessive evaporation in autumn and winter

Fallen leaves are a wonderful mineral and organic fertilizer

Preventing freezing of roots and crumbling seeds

TYPES OF KIDNEYS

KIDNEY - a rudimentary shoot capable of maintaining the viability of meristems for a long time and providing their protection from unfavorable conditions.

A - vegetative - growth of the stem upward

B - vegetative-generative (vegetative propagation reserve)

B - Generative (flowering) – contains the embryos of flowers and inflorescences

1 – rudimentary stem; 2- rudimentary scales; 3 – Rudimentary flowers; 4 – Rudimentary leaves; 5 – rudimentary buds.

Rice. 16 . Escape structure: A – with leaves, B – after leaf fall

A. 1 – stem; 2 – sheet; 3 – node; 4 – internode; 5 – leaf axil; 6 – axillary bud; 7 – apical bud.

B. 1 – apical bud; 2 – kidney rings; 3 – leaf scars; 4 - lateral buds.

Rice. . Aboveground modifications of shoots:

1 – stem succulent; 2 – spine; 3 – phyllocladium of butcher’s broom; 4 – asparagus cladodes; 5 – cabbage bud; 6 – strawberry stolons; 7 – grape mustache; 8 – shortened cherry shoot; 9 – dandelion flower arrow.