Plant Growth Plants, like all living organisms, have the ability to grow and develop. But, unlike many animals, a plant grows throughout its life. Look at an old, almost dry tree - in the spring, young shoots appear here and there, green leaves and its growth continues. Growth stops - the plant dies.
Growth is an increase in the 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 in order to cover the maximum living space.
Plant growth can be continuous or intermittent. With the continuous growth characteristic of most of our annual plants and many tropical species, the size of the organism or its individual parts is constantly increasing.
With periodic growth, growth processes alternate with periods of rest, when the growth of the plant temporarily stops. In plants of cold and temperate climates, the suspension of growth processes is associated with a reduction in the length of the daylight period and the onset of winter.
The reaction of plants to the duration of the light period of the day is called photoperiodism (from the Greek photos and periodos - alternation). The timing of flowering and fruiting of plants depends on this reaction. At tropical plants periodic suspensions of growth are due to 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. In thickness (transverse growth), the organs grow due to the lateral educational tissue (cambia).
The speed and duration of growth is regulated by phytohormones, which, moving through the plant, accelerate or inhibit the growth of certain parts of it. This phenomenon allows a person to control the processes of plant growth. 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 a part of the branches of the crown of a tree, you can awaken and grow dormant buds. These methods are often used in horticulture and park management, and by removing tobacco inflorescences, they achieve an increase in the growth of leaves that 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 a qualitative change that consistently occurs in the body and its individual parts throughout life. An example of development is the formation of a flower. Some of its 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 in the development of a plant.
All transformations that occur in the body from the moment of formation of a zygote to the end of life are called individual development. In the individual development of seed plants, the embryonic and post-embryonic periods are distinguished. The embryonic period begins from the formation of a zygote and continues until the moment of seed germination, 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 to 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 grow intensively and form. A young plant, unlike a seedling, feeds on photosynthesis.
Further development of one-, two- and perennials happens differently. annual plants throughout the year, they completely complete growth, bloom, form seeds and fruits, and die off. The time of their youth is short (dill, peas, cucumbers): already 30–40 days after germination, they form flowers and soon bear fruit. At biennials(cabbages, carrots) in the first year of life, only roots and leaves develop. The following year, they form a flowering shoot, seeds and fruits, and then die off.
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 (e.g. apple, oak, gooseberry, hazelnut, currant) reach their maximum dimensions 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 stage of maturity lasts from the beginning of the first flowering until the cessation of propagation using seeds. Over time, even plants with a long life span stop the formation of generative organs. You must have noticed how old fruit trees bloom less and less often produce fruits. New shoots almost do not appear on them, the old ones dry out and die. In the trunks of old trees, holes are often formed - hollows. This occurs as a result of rotting and dying off of sections of wood.
“For growth, all terrestrial plants need sunlight, 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 keep green plant in the dark, it will soon lose its green color, fade and die. "
"" A plant is 90% water. plant production useful substances photosynthesis is impossible without water. Water helps the plant cells of the plant to remain 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 ndash hormones; chemicals - laquo; controllers, who laquo; order; different plant cells to perform certain functions. Plant hormones are responsible for such things as the development of fruits, the death of petals on flowers and leaves of a plant, and most importantly ndash; they are responsible for growth.
Cells in the tops of stems, new leaves, and buds, for example, produce various growth hormones that tell the plant's cells to divide or expand.
The growth pattern of plants is 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 making food in plants is called photosynthesis. Photosynthesis occurs mainly in leaves. It absorbs sunlight and converts it into energy needed to feed plants. If the plant is placed in a dark place, it will soon lose its green color, then fade and soon die altogether. In the dark, only mushrooms can exist, because they need other plants or inanimate matter to feed.
How do plants eat?
Why do plants need water?
Plants are about 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 eventually the plant dies.
Why are desert plants so far apart?
Desert plants are scattered over a wide area and do not grow very close together because they would have to grow in a constant struggle for water and scarce nutrients. Desert plants have very long roots with which they try to capture more moisture and nutrients. During rains, plants absorb as much water as possible in reserve and store it in a fleshy stem.
How do plants manage to stay cool?
Plant leaves evaporate water, which helps them stay cool. This is possible due to small pores or stigmata. Simultaneously with this process, the roots draw moisture from the soil. Water rises from the roots up the stem. This water carries with it the necessary minerals from the soil.
How climbing plants creep up?
This process varies from plant to plant. Clematis, for example, wraps itself around a stronger plant and is already crawling up 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, in order to climb up the wall, uses small roots. 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, like suction cups, that are attached to a wall or other flat surface awarded ampelopsis. Spikes 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 stay on the surface of the water. The lily has very powerful stems that hold the leaves upright. Exactly water lily and exposes its leaves sunshine without which she cannot survive.
Why do some plants grow thorns?
The spines, sharp needles, and thorns serve to help plants defend themselves against hungry animals and prevent insects from getting in and causing harm. The thistle is very prickly and the cows, eating the grass, do not touch it. Also, the seeds of some plants are highly sticky and, attached to animals, spread over vast areas. Animals bring these seeds far from the plant, where they begin to germinate.
Why does the fetid morel, or veselka, emit such a smell?
The fetid smell that this mushroom emits serves to lure flies. Flies like this smell, and it attracts them, although for us it is simply terrible. Mushroom spores contain mucus that flies feed on. These spores stick to the paws of the flies, and they carry them over long distances. So this fungus with the help of flies spreads over a vast territory.
Why does moss look so much like a thick rug?
Moss grows from spores. Spores, germinating, throw out a thin green thread. Branches grow on this thread, 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 rug absorbs a huge amount of moisture and distributes it evenly over the soil.
How do ferns grow?
The fern does not have flowers, so nature has come up with a different way of reproduction. On inside leaves appear red tubercles. From these tubercles, spores spill out onto the soil, from which plates grow. They contain both female and male cells, which subsequently fuse. And even these plates grow a new fern. Some types of ferns reproduce by underground stems, such as the bracken.
Do plants have a sense of time?
Most plants determine the seasons with amazing accuracy.” Flowering constantly bloom in the same period. Some plants, like animals, store nutrients in underground roots and stems for the winter period. 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 the Venus flytrap and the sundew, grow in swampy soil that is very poor in minerals that the plants need to survive. These plants have acquired traps for catching various kinds 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, as it instantly slams shut. The plant secretes acid, in which the victim is digested. The acid decomposes the insect into the necessary nutrients for the plant.»»»»»»»»»»»»»»»»
Change of plants during life
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heading
Phenological spectra. tillering. Exit to 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 are there a large number of phenological phases in cereals?
4. What are the tillering and booting subphases in bread crops
5. How do the local climate and weather influence the onset and duration of phenological phases? Give examples.
Remember! Tree, shrub, shrub. Cover fabrics. Deserts. Ephemera.
However, the bud rings are clearly visible on relatively young thin branches. On the older ones, as their stems thicken and the outer layers of the covering tissue slough off, the buds become difficult to distinguish and gradually completely disappear.
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 saw cut :: stems.
Tree age. The age of trees is also determined by the number of growth rings of wood on the trunk cut. In this way, it was found that oak trees live 1300 years, larch - 600 years, maple - 200 years, mountain ash - 80 years. However, this method can be used to determine the age of felled, i.e., dead trees, and therefore this method is unsuitable for rare protected species, for example, yew berry, mammoth tree (Fig. 81), and durable pine.
In protected trees, thin, pencil-thick cylinders of wood are drilled to the center of the trunks with a special drill and annual rings are counted on them. It doesn't hurt the tree great harm. Thus, 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 durable pine - 4000-4600 years. Such old trees began their lives during the construction of the pyramids in Egypt and the settlement of Europe by primitive tribes.
According to the width of annual rings a; wood of long-lived trees, scientists have restored the picture of climate change on Earth in
the last 3-4 thousand years. The fact is that the width of the growth 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."
Longevity of shrubs and shrubs. Shrubs have not one trunk, but many trunks, each lives 5-15 years (this can be established both by the number of kidney rings and by the cuts of the trunks). The stems gradually replace each other. To determine the age of a shrub, for example, a hazel hazel, it is necessary to calculate the total number of stems and establish how many of them arise (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 terms of durability. Hazel, for example, lives 120-200 years.
It is even more difficult to establish the age of shrubs: blueberries (Fig. 82), blueberries, marsh wild rosemary. Using the method of counting kidney 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 is a set of 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 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, that is, their age is quite comparable to the age of shrubs and trees.
How long do herbs live. All
know that herbs are annuals, biennials and perennials. Annual herbs, such as rye, dill, wild radish, have time to grow from seeds in one year, bloom and give mature seeds. Among annuals, there are types of ephemera, the whole life of which passes in three to four weeks. IN central Russia ephemera include small mousetail, spring grits, sickle-shaped hornhead (Fig. 83).
Biennial herbs, such as carrots, cobwebbed 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 off.
The vast majority of forest, lulova and marsh grasses are perennials. After germination from the seed for the first time, they bloom only for 3-10 years of life. Then they bloom, as a rule, annually. In autumn, the above-ground parts of the shoots die off, and the surface and underground parts bear buds, from which new above-ground shoots grow in the spring.
How long do they live perennial herbs? Can you determine their age? These questions are difficult to answer for two reasons. Firstly, in perennial grasses, their underground parts are not completely preserved, but gradually die off and are destroyed. Secondly, for perennial grasses, unlike trees, there is no single way to determine the age. The life span of herbaceous perennials is determined in different ways. For example, in feather grass, shuchka, belous and other densely tufted plants
measure the diameter of the turf. Every year, the tufts increase in diameter by about 0.3-0.5 cm. Therefore, a pike plant with a tuft of 30 cm in diameter has an age of about 60 years.
In short-rooted forest ferns, for example, male boletus, female boletus, the number of accumulating scales on rhizomes is counted. These scales are the bases of dead leaves. Every year, ferns usually develop 5-7 leaves. 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 boletus lives 40-50 years, and the female boletus lives 60-70 years. Thus, perennial grasses live for decades. Scientists have found that meadow timothy, fragrant spikelet, meadow fescue, thin bent grass live 5-15 years, Siberian hogweed, rapunzel-shaped bell - 5-10, dandelion - 10-20, and white-bearded - 30-50, feather grass - 60- 80 years old. Unfortunately, not all herbs can determine the life span.
All plants are living organisms, so they grow and develop. Many people are interested in how plants grow, how it happens. Do you also want to know how a huge tree grows from a small seed? Now we will consider in detail 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, you need to understand what makes plants grow in length and thickness.
The plant increases in length due to cell division of a special tissue called educational. The thickening of the plant occurs due to the educational tissue, which is called the cambium. At the time of flowering, as well as in the interval between autumn and spring, the cells of this tissue no longer divide.
Before you find out for yourself where plants grow, it is worth talking about the conditions for their growth.
growth conditions
As you know, plants need heat, since substances (enzymes) that accelerate the reactions of growth and development will not work at low temperatures.
Light is necessary in order for the photosynthesis reaction to constantly proceed, as a result of which organic substances are formed, oxygen is released from water and inorganic substances. Many plants love the light, but there are also plants that grow in the shade.
Plants get their nutrients from water, without it metabolism is impossible, and 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 some plants are specially grown by a person in special conditions in the territories allocated for this, including in their 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, showing aggressive behavior towards cultivated plants.
Where do plants grow? Look around - 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. And what these conditions are, we have already discussed a little higher.
The child is interested in everything around. Why is the sky blue and the sea salty? Every day, "why" make us think how easy it is to explain the complex. In this article we will talk about how a flower grows for children: step by step and understandable.
A little about plants and flowers
Imagine a flower bed with roses in bloom. Speaking of roses, we often call the whole 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 are very different from each other. For example, oak seeds are acorns, cherry seeds are the seeds inside its berries, and tiny poppy seeds are often seen on baked goods. Usually the seeds are small, but among them there are giants such as coconut.
Seeds look for themselves in different ways new house: someone flies towards him, picked up by the wind, someone floats on the water. Birds and animals help many plants to travel around the world. Seeds of various plants take root in different places, but everyone needs water and warmth to thrive.
Rooting
A seed that has fallen into suitable soil, lets out roots. From now on, they will perform many important tasks, supporting the life of the plant.
Roots grow down. Usually they look like the crown of trees turned upside down, but the roots of different plants (as well as the same, growing in dissimilar conditions) are different.
Roots draw out gases, water, organic and mineral substances dissolved in it from the soil - that is, everything that replaces food for the plant. Roots can bring out harmful substances and keep the useful ones. And, of course, the roots firmly fix the plant in the ground, preventing strong winds and streams of water from destroying it.
Roots are the most important part of a plant. As long as they are healthy and remain in the ground, the plant will not die. Plucked branches and stems, flowers and leaves will surely grow again.
The emergence of a sprout
After the roots are released, the first shoot hatches. It breaks through a seed like a chicken through an eggshell 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 a seedling. A thin stem with a pair of leaves will develop into an adult plant. To do this, he needs the sun, water and air, as well as the nutrients that the roots take in the soil.
Plants have different needs. Someone needs warmth and bright sun, while someone feels good in the shade and coolness. Some plants need a lot of water, some less. IN right conditions seedlings stretch and grow. Along with the visible part of the plant, roots develop.
Maturity, flowering and the circle of life
The time comes, and flowers appear on an adult plant. This happens when the plant builds up enough energy to produce its own seeds.
A bud appears on the stem of the plant, at first it looks like an ordinary folded leaf. It develops to 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.
