Plant growth Plants, like all living organisms, are capable of growing and developing. But, unlike many animals, the plant grows throughout its life. Look at an old, almost dry tree - in the spring, young shoots and green leaves appear here and there and its growth continues. Growth stops and the plant dies.
Growth is an increase in size, volume and mass of both the whole organism and its individual parts. That is, growth is quantitative changes in the body. It is caused by cell division and growth. Another feature of plants is that they grow in one place. Therefore, they need an increase in all parts to cover the maximum living space.
Plant growth can be continuous or periodic. With the continuous growth characteristic of most of our annual plants and many tropical species, the size of the organism or its individual parts increases constantly.
With periodic growth, growth processes alternate with periods of rest when plant growth temporarily stops. In plants of cold and temperate climates, the suspension of growth processes is associated with a reduction in the duration of the daylight period and the onset of winter.
The reaction of plants to the length of the daylight period is called photoperiodism (from the Greek photos and periodos - alternation). The time of flowering and fruiting of plants depends on this reaction. U tropical plants Periodic growth stops are caused by the onset of the dry season.
As you remember, depending on the location of the educational tissue, apical and intercalary types of organ growth are distinguished. The organs grow in thickness (transverse growth) due to the lateral educational tissue (cambium).
The speed and duration of growth is regulated by phytohormones, which, moving throughout the plant, accelerate or inhibit the growth of certain parts of it. This phenomenon allows humans to control plant growth processes. Remember how, by splitting off the top of the main root, you can enhance the formation of lateral and additional roots. You also know that by cutting off part of the branches of the tree crown you can awaken and grow dormant buds. These methods are often used in gardening and park management, and by removing tobacco inflorescences, they achieve increased growth of leaves, which serve as raw materials for the tobacco industry.
Plant development. We often say that a plant grows and develops. The development of plants is closely related to their growth, but they are not the same thing. Development is qualitative changes that consistently occur in the body and its individual parts throughout life. An example of development is the formation of a flower. Its individual parts also grow, but in general its appearance is a new qualitative state of the whole organism. Therefore, flowering is an indicator of a certain stage of plant development.
All transformations that occur in the body from the moment the zygote is formed until the end of life are called individual development. In the individual development of seed plants, embryonic and post-embryonic periods are distinguished. The embryonic period begins with the formation of the zygote and continues until the germination of the seed, after which the post-embryonic period begins. It includes the stages of seedling, youth, maturity and old age.
The seedling stage lasts from the moment of germination until the formation of the first green leaves. At this time, the seedling feeds on the reserve nutrients of the seed.
The youth stage is the period of life from the appearance of the first green leaves to the beginning of flowering. At this time, all the vegetative organs of the plant are intensively growing and forming. A young plant, unlike a seedling, is nourished by photosynthesis.
Further development of one-, two- and perennial plants happens in different ways. Annual plants Over the course of a year, they completely complete growth, bloom, form seeds and fruits, and die. Their youth period is short (dill, peas, cucumbers): already 30–40 days after germination they form flowers and soon bear fruit. U biennial plants(cabbage, carrots) in the first year of life, only roots and leaves develop. The next year they form flowering shoots, seeds and fruits and then die.
Perennial herbs can bloom and bear fruit for several years, but all their above-ground parts die off annually (for example, lily of the valley, wheatgrass, horseradish).
Woody perennial trees and shrubs (for example, apple tree, oak, gooseberry, hazelnut, currant) reach their maximum sizes after tens, or even hundreds of years, and their first flowering and fruiting occurs only a year later, sometimes several years after germination. They bear fruit for many years.
The maturity stage lasts from the beginning of the first flowering until the end of propagation by seeds. Over time, even plants with a long life period stop forming generative organs. You've probably noticed how old fruit trees They bloom less and less often and produce fruit less and less often. New shoots almost never appear on them, old ones dry out and die. Holes - hollows - often form in the trunks of old trees. This occurs as a result of rotting and dying of sections of wood.
“All earthly plants need sunlight to grow, because it is involved in the process of their nutrition. Food creation, or photosynthesis, occurs primarily in leaves, where chlorophyll absorbs sunlight and converts it into energy. If you hold green plant in the dark, it will soon lose its evil color, fade and die. "
"" The plant is 90% water. Plant production useful substances through photosynthesis without water is impossible. Water helps the plant cells stay resilient. If there is not enough water, the cells weaken and the plant dies. Most plants constantly need water obtained through the root system.”
Special plant cells produce hormones ndash; chemicals - laquo;controllersraquo;, which laquo;order; different plant cells perform specific functions. Plant hormones are responsible for such things as the development of fruits, the death of petals on flowers and leaves of the plant, and most importantly ndash; they are responsible for growth.
Cells in the tips of stems, new leaves, and buds, for example, produce various growth hormones that instruct plant cells to reproduce by fission or enlarge.
The growth pattern of plants provides an illustration of how they differ from animals. While animals grow to full size after some time (and live for a long time after that), plants grow throughout their entire life cycle. In other words, such a thing as mature plant, which has stopped growing but continues to live, simply does not exist.
How do plants grow?
How do plants eat?
Why do plants need water?
How do ferns grow?
How do plants grow?
Can plants live without sunlight?
Without exception, all plants on earth need sunlight because it is necessary for the process of their nutrition. The process of creating food in plants is called photosynthesis.” Photosynthesis occurs mainly in the leaves. It absorbs sunlight and converts it into energy needed to power plants. If the plant is placed in a dark place, it will soon lose its green color, then it will fade and soon die completely. Only mushrooms can exist in the dark, because they need other plants or inanimate matter to feed
How do plants eat?
Why do plants need water?
Plants are approximately 90% water. Nutrients obtained by plants through photosynthesis cannot be produced without water. Almost all plants need water, which they receive through the root system. Water helps plant cells stay resilient. If there is not enough water, the cells become weak and the plant eventually dies.
Why are desert plants located at a considerable distance from each other?
Desert plants are scattered over a wide area and do not grow very close to each other because they would have to grow in constant competition for water and scarce nutrients. Desert plants have very long roots, with which they try to capture more moisture and nutrients. During the rains, the plants absorb as much water as possible in reserve and store it in the fleshy stem.
How do plants stay cool?
Plant leaves evaporate water, which helps them stay cool. This is possible due to small pores or stogmata. Simultaneously with this process, the roots draw moisture from the soil. Water rises from the roots up the stem. This water carries with it essential minerals from the soil.
How climbing plants crawling up?
This process occurs differently in different plants. Clematis, for example, wraps itself around a stronger plant and crawls upward along it. In clematis, one half grows much faster than the other, as a result of which it begins to curl around the other plant. Ivy uses small roots to climb up the wall. There are also owners of special twisted antennae with which they cling to the wall. These include, for example, regular and sweet peas. Small pads, similar to suction cups, that are attached to a wall or other flat surface awardedampelopsis. The thorns cling to everything possible to help climbing roses and brambles grow upward.
Why don't water lily leaves sink?
On inner surface The leaves of the water lily have cavities filled with air. These cavities help them float on the surface of the water. Lilies have very powerful stems that hold the leaves upright. Exactly water lily and exposes its leaves sunlight, without which she cannot survive.
Why do some plants grow thorns?
The spines, sharp needles and thorns serve plants to help protect them from hungry animals and prevent insects from entering and causing harm. Thistle is very prickly and cows, eating the grass, do not touch it. Also, the seeds of some plants are very sticky and, having attached themselves to animals, are spread over vast territories.” Animals carry these seeds far from the plant, where they begin to germinate.
Why does the foul morel, or veselka, emit such a smell?
The foul smell that this mushroom emits serves to attract flies. Flies like this smell and are attracted to it, although for us it is simply terrible. Fungal spores of the Veselka contain mucus, which flies feed on. These spores stick to the flies' legs, and they carry them over long distances. This is how this fungus spreads over a vast area with the help of flies.
Why does moss look so much like a thick rug?
Moss grows from spores." When spores germinate, they emit a thin green thread. On this thread, branches grow, on which buds form. New shoots are formed from these buds. The newly emerged plants are very close to each other and soon a mat is formed. This moss mat absorbs a huge amount of moisture and distributes it evenly throughout the soil.
How do ferns grow?
Ferns do not have flowers, so nature came up with another method of reproduction. On inside red tubercles appear on the leaves. From these tubercles, spores spill out onto the soil, from which plates grow. They contain both female and male cells, which subsequently connect. And even from these plates a new fern grows. Some types of ferns reproduce from underground stems, such as the bracken fern.
Do plants have a sense of time?
Most plants determine the time of year with amazing accuracy.” Flowering plants constantly bloom at the same period. Some plants, like animals, store nutrients in underground roots and stems for the winter. All this is regulated in plants by the changing length of day and night throughout the year.
Can plants eat insects?
Insectivorous plants, such as Venus flytraps and sundews, grow in marshy soil that is very poor in the minerals that plants need to survive. These plants have acquired traps for catching various types of insects. Traps are not the main source of food. There are traps at the tips of the flycatcher's leaves. It is enough for an insect to touch one of the hairs of the trap, and it instantly slams shut. The plant secretes acid in which the victim is digested. The acid breaks down the insect into essential nutrients for the plant.»»»»»»»»»»»»»»
Changes in plants throughout life
Li.oua X
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Phenological spectra. Tillering. Output into the tube.
Phenology. Phenological phases (phenophases).
1. What does phenology study?
2. Name the main phenological phases of plants in the temperate zone.
3. Why do cereals have a large number of phenological phases?
4. What are the subphases of tillering and booting in grain crops?
5. How do the local climate and weather affect the timing and duration of phenological phases? Give examples.
Remember! Tree, bush, shrub. Integumentary tissues. Deserts. Ephemera.
However, the bud rings are clearly visible on relatively young thin branches. On older ones, as their stems thicken and the outer layers of the skin tissue peel off, the bud rings become difficult to distinguish and gradually disappear completely.
Rice. 81. Rare protected trees 1 - yew, berry; 2 - mammoth tree
The age of old thick branches has to be determined in a different way - by the number of annual rings of wood per cut: stems.
Age of trees. The age of trees is also determined by the number of annual rings of wood on the cut trunk. In this way, it was established that oak trees live 1300 years, larch trees - 600 years, Norway maple trees - 200 years, and mountain ash trees - 80 years. However, this method can determine the age of cut down, i.e., dead trees, and therefore this method is unsuitable for rare protected species, for example, yew berry, mammoth tree (Fig. 81), and long-lived pine.
In protected trees, thin, pencil-thin cylinders of wood are drilled out to the center of the trunks with a special drill and the growth rings on them are counted. It doesn't hurt the tree great harm. In this way, it is possible to preserve the tree and determine its age. It turned out that yew berry lives 1800 years, and growing in North America mammoth tree and pine are durable - 4000-4600 years. Such old trees began their life back during the construction of the pyramids in Egypt and the settlement of Europe by primitive tribes.
Based on the width of the growth rings of wood in long-lived trees, scientists have reconstructed patterns of climate change on Earth over the course of time.
the last 3-4 thousand years. The fact is that the width of the annual rings of wood is determined by weather conditions: in wet and warm years, wide rings are formed, in dry and cold years, narrow ones. The structure of wood thus reflects fluctuations in weather and climate. No wonder back in the 19th century. Foresters have a saying: “A tree is a chronicle of nature.”
Lifespan of shrubs and shrubs. Shrubs have not one trunk, but many stems, each one lives 5-15 years (this can be determined both by the number of bud rings and by the cuts of the stems). The stems gradually replace each other. To determine the age of a shrub, for example hazel, you need to count the total number of stems and determine how many of them appear (and die) in one year. Dividing the first number by the second and multiplying the result by the lifespan of one stem, we get the total lifespan of the shrub. It turned out that shrubs compete with trees in durability. Hazel, for example, lives 120-200 years.
It is even more difficult to establish the age of shrubs: blueberries (Fig. 82), blueberries, wild rosemary. Using the method of counting bud rings, it can be determined that individual blueberry bushes live 15-25 years. Under the ground, the bushes are connected to each other by long rhizomes. As the old bushes die off, they are replaced by new young ones. One plant
 Rice. 82. Blueberry plants with underground parts |
blueberry plant consists of many bushes connected to each other by long branching rhizomes. The age of blueberries can be determined by counting the number of bushes formed over the entire life of the plant. To do this, it is necessary to carefully excavate the underground parts. Scientists have found that blueberries live for 100 years or more, i.e., their age is quite comparable to the age of shrubs and trees.
How long do herbs live? All
They know that herbs are annual, biennial and perennial. Annual herbs, such as rye, dill, and wild radish, have time to grow from seeds, bloom, and produce mature seeds in one year. Among annuals there are species of ephemerals whose entire life passes in three to four weeks. IN Central Russia ephemerals include the small mousetail, the spring croup, and the sickle-shaped cornea (Fig. 83).
Biennial herbs, such as carrots and cobweb burdock, form only vegetative shoots in the first year of life and accumulate reserve substances in the underground parts. Biennials bloom and bear fruit only in the second year of life. After seeding, biennials die.
The vast majority of forest, grass and marsh grasses are perennials. After germination from a seed, they bloom for the first time only at 3-10 years of age. Then they bloom, as a rule, annually. In the fall, their above-ground parts of the shoots die, and the above-ground and underground parts bear buds, from which new above-ground shoots grow in the spring.
How long do they live perennial herbs? Is it possible to determine their age? Answering these questions is difficult for two reasons. Firstly, in perennial grasses their underground parts are not preserved entirely, but gradually die off and are destroyed. Secondly, for perennial grasses, unlike trees, there is no single method for determining age. The lifespan of herbaceous perennials is determined in different ways. For example, in feather grass, shuchka, white grass and other dense turf plants
measure the diameter of the turf. Every year the turf increases in diameter by about 0.3-0.5 cm. Therefore, a pike plant with a turf 30 cm in diameter is about 60 years old.
In short-rooted forest ferns, for example, male shield fern and female fern, the number of storage scales on the rhizomes is counted. These scales represent the bases of dead leaves. Ferns usually develop 5-7 leaves each year. If we divide the total number of rhizome scales by seven, we get the approximate age of the plant. It turned out that the male stink bug lives 40-50 years, and the female stink bug lives 60-70 years. In this way, perennial grasses live for decades. Scientists have established that meadow timothy, fragrant spikelet, meadow fescue, thin bentgrass live 5-15 years, Siberian hogweed, rapunzel bell - 5-10, dandelion - 10-20, and white grass - 30-50, feather grass - 60- 80 years old. Unfortunately, it is not possible to determine the lifespan of all herbs.
All plants are living organisms, so they grow and develop. Many people are interested in how plants grow and how this happens. Do you also want to know how a huge tree grows from a small seed? Now we will take a closer look at the process of plant growth.
As you know, an adult plant does not appear on its own. Many plants grow from an ordinary, sometimes very small, seed. First, a small sprout appears from the seed, which subsequently gradually becomes a young plant. Over time, the young plant develops and turns into an adult.
To fully understand why plants grow, it is necessary to understand what causes plants to grow in length and thickness.
The plant increases in length due to the division of cells of a special tissue called educational tissue. Thickening of the plant occurs due to educational tissue called cambium. At the time of flowering, as well as between autumn and spring, the cells of this tissue no longer divide.
Before you find out for yourself where plants grow, it’s worth talking about their growth conditions.
Growth conditions
As you know, plants need heat, since substances (enzymes) that accelerate growth and development reactions will not work at low temperatures.
Light is necessary for the photosynthesis reaction to constantly occur, as a result of which organic substances are formed and oxygen is released from water and inorganic substances. Many plants love light, but there are also plants that grow in the shade.
Plants receive nutrients from water; without it, metabolism is impossible, and the air is a source of carbon dioxide.
Plant species
All plants can be divided into cultivated and wild. This division is due to the fact that people specifically grow some plants in special conditions in areas designated for this, including in your own garden, while others grow in nature on their own.
Cultivated plants are quite developed compared to wild ones, their organs are quite large in size. A wild plants(weeds) grow as they please, exhibiting aggressive behavior towards cultivated plants.
Where do plants grow? Look around you - plants are everywhere! These are plants in parks and forests, and vegetables in my mother’s garden, and houseplants in the apartment. Plants grow wherever there are conditions for their growth. We have already discussed what these conditions are a little higher.
The child is interested in everything around him. Why is the sky blue and the sea salty? Every day “whys” force us to think about how to simply explain complex things. In this article we will talk about how a flower grows for children: step by step and clearly.
A little about plants and flowers
Imagine a flowerbed with roses blooming. When talking about roses, we often call the entire plant a flower: stems, leaves, and buds. Although this is not entirely true.
A rose is a flower, but the bush from which we cut it is a plant. We will understand how a flower grows if we first talk about the plant itself.
The seed falls into the soil
It all starts with seeds. The seeds of different plants differ greatly from each other. For example, oak seeds are acorns, cherry seeds are the seeds inside its berries, and we often see tiny poppy seeds in baked goods. Usually the seeds are small, but among them there are also such giants as coconut.
Seeds are looked for in different ways new house: someone flies towards him, caught by the wind, someone swims on the water. Birds and animals help many plants travel around the world. Seeds of different plants take root in different places, but everyone needs water and warmth to ascend.
Root formation
A seed that falls into suitable soil sends out roots. From now on, they will perform many important tasks to support the life of the plant.
The roots grow downwards. Usually they look like the crown of trees turned upside down, but the roots of different plants (as well as the same ones growing in different conditions) are different.
Roots pull gases, water, organic and mineral substances dissolved in it from the soil - that is, everything that replaces food for the plant. Roots can come out harmful substances and keep the useful ones inside. And, of course, the roots firmly anchor the plant in the ground, preventing strong winds and streams of water from destroying it.
The roots are the most important part of the plant. As long as they are healthy and remain in the ground, the plant will not die. Torn branches and stems, flowers and leaves will definitely grow again.
Appearance of a sprout
After the roots are released, the first shoot hatches. He breaks through the seed like a chicken through an egg shell, and reaches up through the earth to see the sun.
A little time will pass and the sprout will appear on the surface where we can see it. From now on we can call it sunrise. A thin stalk with a pair of leaves will develop into a mature plant. To do this, it needs sun, water and air, as well as nutrients that the roots take from the soil.
Plants have different needs. Some people need warmth and bright sun, while others feel good in the shade and coolness. Some plants need a lot of water, some less. IN the right conditions the seedlings stretch out and grow. Along with the visible part of the plant, the roots also develop.
Maturity, flowering and the circle of life
The time comes, and flowers appear on the adult plant. This happens when the plant accumulates enough strength to produce its own seeds.
A bud appears on the stem of the plant, at first similar to an ordinary folded leaf. It develops into a bud. When the bud opens, we finally see the flower.
Insects carry pollen from one flower to another. This process is called pollination, and after it is successfully completed, the plant produces new seeds.
The seeds are carried around by wind, water or animals, and everything starts all over again. This is the circle of life that plants go through.
