The period of a plant's life when growth slows down sharply. Why does tomato seedlings grow poorly, and what to do in this case? Reasons for the slow growth of a tomato. How to improve the harvest

Growth - is the process of new formation of structural elements

organism, which include organs, tissues, cells, cell organelles. Growth is accompanied by an increase in the mass and size of the plant. Unlike animals, plants grow throughout their lives, forming new cells, tissues and organs.

Development - these are qualitative changes in the structure and functional activity of the plant and its parts in the process of its individual development (ontogenesis). Growth and development are closely related to each other and occur simultaneously. Growth is one of the properties of development, and development cannot proceed without growth; it needs at least a barely begun growth. In the future, the development process is decisive.

The basis of plant growth is the division and growth of meristematic cells. Cell growth occurs in three phases: embryonic, stretching and differentiation.

AT embryonic phase growth is carried out due to the division of the meristematic cell with the formation of daughter cells. Daughter cells increase in size and, reaching the size of the parent, divide again. These processes require large amounts of nutrients and energy.

Stretch phase characterized by a significant increase in cell size. Vacuoles appear in them, which gradually; merge into one big one. The cell wall is stretched, its new dimensions are fixed by the inclusion of cellulose microfibrils.

After the deposition of cellulose molecules inside and especially on the surface of the primary membrane (secondary thickening), the extensibility of the cell membrane decreases, and the turgor increases, which stops the process of absorption of water by the cell.

During this period, the cell gradually loses its ability to further stretch.

AT phase of differentiation the final formation of the cell occurs, its transformation into a specialized one, i.e. performing a certain specific function: water-conducting (xylem vessels and tracheids), conducting organic substances (phloem sieve tubes), storage (pa-

renchyma), mechanical (libriform), etc.

growth regulators.

Growth is due to heredity and is regulated with the help of specific physiologically active substances - phytohormones and inhibitors. The first cause acceleration of growth and development, the second, on the contrary, limit growth. An important role in the regulation of plant growth with the help of phytohormones is played by their concentration. Growth stimulation is observed only at very low concentrations of these substances in plant cells; high concentrations can act as inhibitors.

Phytohormones include auxins (indolylacetic acid IAA), gibberellins, and cytokinins. Natural inhibitors are abscisic acid, phenolic inhibitors, ethylene.

The general properties of phytohormones are as follows: each hormone is involved in the regulation of a number of structural and functional processes, i.e. has polyfunctional properties; the strength and nature of the action of hormones depend on the concentration; In a plant, hormones do not act in isolation, but in close interaction with each other. Hormones are formed in small amounts mainly in meristematic tissues, as well as in leaves and from them move to those parts of the plant where growth or morphogenesis processes occur.

Auxins activate cell division and elongation, participate in growth movements, provide apical dominance - suppression of lateral growth by the apical bud, stimulate root formation.

Gibberellins enhance the growth of the stem in length, accelerate the growth of fruits and seed germination.

Cytokinins accelerate cell division, delay the aging of leaves, callus tissues cause the formation of shoots, interrupt the dormancy of dormant buds, increase plant resistance to adverse effects.

Natural growth inhibitors suppress the action of phytohormones or inhibit their synthesis. They are widely distributed in seeds, dormant buds. They are also associated with lignification of shoots of woody plants, which contributes to their successful overwintering.

Abscisic acid regulates the processes of aging and leaf fall, ripening of fruits, stimulates the transition to rest of the kidneys, seeds, bulbs. Regulates the movement of stomata during drought. This acid is called the stress hormone, as its amount increases under adverse conditions.

Ethylene inhibits cell division, promotes tissue aging, accelerates leaf fall, fruit ripening.

Phenolic compounds regulate the amount of auxins in the cell, and also participate in the regulation of root formation, cell elongation.

Synthetic plant growth regulators are widely used in plant growing practice. They are used in pre-sowing seed treatment, rooting cuttings, transplanting vegetable and flower crops, as well as mature woody plants.

Basic patterns of growth

In nature, plants experience alternation of periods of intensive growth and slowing down or complete cessation of growth. This phenomenon is called periodicity of growth and associated with the change of seasons. In autumn, plants shed their leaves, and sometimes entire shortened shoots, stop growing and fall into a dormant state. Distinguish daily and age growth frequency. The daily frequency of growth depends on temperature. Most of our tree species grow most intensively in height at the age of 20 - 30 years, and the increase in trunk volume usually reaches maximum values ​​​​at 50 - 60 years.

Peace is the state of a plant in which there is no visible growth. It is characterized by a reduced water content in plant tissues, a weakened metabolism and reduced respiration. Not the whole plant often goes into a dormant state, but its individual organs, for example, dormant buds, seeds. There are two types of rest: organic and forced. At organic peace the plant and its organs do not come out of dormancy even under favorable conditions. Deep dormancy is characteristic of the seeds of many tree species. Under forced rest understand such a physiological state of seeds, buds, shoots, in which they cannot bloom due to adverse external conditions (lack of water, low temperature).

All parts of the plant have a mutual influence on each other, they are coordinated with each other. This phenomenon is called cor- relation growth. So, for example, the central shoot is ahead of the lateral ones in the ro-et, but it is worth damaging the apical bud or removing the upper part of the central shoot, as the lower branches begin to grow vertically, taking on the functions of the apical shoot. This technique is widely used in gardens and landscape plantings in the formation of tree crowns. The inhibitory effect of the apical kidney on the lateral is called apical dominance. A similar correlative inhibition is observed at the roots. "Nipping" the main root leads to the formation of numerous lateral roots. Growth correlation is based on hormonal regulation of the redistribution of nutrients and physiologically active substances in the plant.

Polarity plants is a specific orientation of structures and processes in space. It manifests itself in the formation of shoots at the morphologically upper end of the stem cutting, and roots at the morphologically lower end, regardless of whether the cutting is in a straight or inverted position. The phenomenon of polarity is associated with the transport of auxin along the phloem from the morphologically upper end to the lower one. Polarity ensures the organization in space of individual parts of an organism, the division of functions along the axis of the plant.

plant movements

The reason that causes a change in the arrangement of plant organs in space is an external factor. In response to the unilateral action of the factor, bends occur in plants, leading to a change in the orientation of the organ. These movements, caused by a unilaterally acting stimulus, are called tropisms. If the bend is caused by the directional action of light, this is phototropism, gravity - geotropism, uneven distribution of moisture in the soil - hydrotropism, nutrients - chemotropism. Due to positive phototropism, plants form sheet mosaic, those. leaves in space are arranged so as to maximize the use of light. The most striking example of chemotropism is the growth of roots towards higher concentrations of nutrients in the soil.

Nastyami are called growth movements that occur in response to the action of diffuse, i.e. not having a strict direction, factors. These factors include temperature (termonasty), light (photonasty), etc. Nastia is characteristic of leaves, petals, and sepals. An example is the opening and closing of flowers during the change of day and night. One of the factors resulting in nastia is uneven cell growth by stretching. In most cases, nastic bends are turgor movements. They are carried out due to the increase and decrease in the vacuoles of specialized cells of osmotically active substances, as a result of which the turgor pressure changes. The process of opening and closing of stomata is associated with a change in turgor pressure in guard cells.

Plant growth is due to division and sprains cells various organs. Growth processes are localized in meristems. Distinguish apical, intercalary and lateral meristems.

Apical , or apical, meristems are located at the ends growing shoots and tips roots all orders ( apexes, or points of growth). Taper escape apex called growth cone. Due to these meristems, the growth of axial organs is carried out. in length, education rudiment of an organ and its initial division into fabrics. By activating or suppressing the activity of the apical meristem, it is possible to influence the productivity and resistance of plants. According to V.V. Polevoy (1989), the apical meristems of the shoot and root are the main coordinating (dominant) centers plants that determine its morphogenesis.

Due intercalary (intercalary) meristem located at the base of young internodes grows stem and leaves of monocots plants.

Lateral (lateral) meristems provide thickening stem and root: primary - procambium and pericycle and secondary - cambium and phellogen. The constant growth of a plant at all stages of ontogenesis allows it to meet the needs for energy, water and mineral nutrients.

The activity of meristems depends on the influence of external conditions, complex relationships within the plant organism (polarity, correlation, symmetry, etc.). In the village - x. practice through watering, top dressing, thinning and other measures can influence the number of metameric organs laid in the growth cones, on their subsequent growth, reduction and, as a result, on plant productivity.

1. Features of the growth of plant organs

stem growth. The stem apex measures 0.1-0.2mm in dimeter and protected by leaves. Stem elongation occurs due to the growth of internodes. First, the upper internodes grow. The next internode passes to intensive growth with a decrease in its rate at the previous one. Each individual internode is characterized slow initial growth(cell division), subsequent rapid growth (stretching cells) and finally growth retardation in a mature internode.

At growing internodes outdoor fabrics are tested tension(stretch) and internal- compression ( compression), which, along with the turgor pressure of the cells, provides strength stems of herbaceous plants.

AT favorable conditions the longest internodes are formed in middle part escape.

Lateral branching comes from the growth axillary or sprouting adnexal(adventive) kidneys.

Thickening - result of activity lateral meristem - cambium. At annual plant division cambium ends in bloom. At woody cambium forms from autumn to spring ( winter) is in the state rest(determines the presence growth rings).

The rate of elongation of the stem of the shoots is regulated by incoming auxins and gibberellins. Intensively growing internodes are characterized by increased content of gibberellins and auxins.

plant height determined by their genome, and to a large extent - by growing conditions.

Bookmark generative organs associated with photoperiodic sensitivity vernalization and other factors. At cereals ear differentiation begins in the tillering phase.

leaf growth. Several leaf buds are present in the germinal bud, but most of them are formed after germination. Rudimentary leaves appear on the growth cone of the shoot (from ridges or tubercles - primordia). The interval between the initiation of two leaf primordia in different plants ranges from several hours to several days and is called plastochrone . For the formation of primordia and leaf tissues, cytokinin and auxin. Auxin affects the formation of vascular bundles, and gibberellin - the elongation of the leaf blade.

At dicots leaf blade is enlarged by uniform cell growth(mostly by stretching) throughout the area sheet. Availability several points of growth defines education teeth, blades, leaves.

At monocots the sheet is lengthened by basal and intercalary growth.

Thickening leaf is carried out due to the division and stretching of the cells of the palisade parenchyma and mesophyll cells.

Leaf growth is strongly influenced by intensity and quality of light. In the dark leaf growth is retarded. Light stimulates fission, but inhibits stretching cells. In shade, the leaves are larger and thinner. . intense light causes thickening leaf blades due to the formation additional layers of columnar parenchyma.

At lack of water small leaves with a xeromorphic structure are formed, which is associated with an increase in ABA and ethylene.

At nitrogen deficiency the number of cell divisions decreases during the period of leaf growth, its surface is reduced.

Low temperature slows down leaf growth in length and stimulates thickening. Wherein in frost-resistant varieties In winter wheat, the duration of the cell elongation phase is reduced to a greater extent than in unstable wheat.

Growth sheet stops when the intense export photosynthesis products.

root growth. The rate of cell division and growth in the roots is much higher than in other organs of the plant. Primary the root is formed in embryo seed, and its growth before leaving the seed occurs by sprains basal cells of the meristem of the germinal root. At dicots plant germinal root becomes main(pivotal), forms lateral roots. At monocots plants, the primary root is supplemented by adventitious roots formed at the base of the shoot, is formed fibrous root system.

When germinating seed appears embryonic root, which fast growing, then its growth rate are declining while accelerating the growth of above-ground organs. In the future, the growth of the root again resumes. These features ensure the rooting at the first stage and the harmonious development of the heterotrophic and autotrophic parts of the plant in the subsequent period.

Apical meristem root forms root cap , which performs very important functions (protects the meristem when the root moves in the soil; secrete polysaccharide mucus and constantly peel off from its surface; mucus protects against pathogens and drying out; is sensory area, perceiving the action of gravity, light, soil pressure, chemicals and determines the direction and speed of root growth; it synthesizes ABA).

On the border with the cap in the meristem are resting center cells , which includes initial cells of different tissues 500-1000 cells). resting center restores the number of meristem cells due to natural wear or damage.

At the roots of all types, 4 zones : division , sprains , root hairs and holding (branching).

At the roots corn, peas, oats, wheat and others growing part is short - less than 1 cm. The thinner the root, the shorter its meristem. Fundamentally short stretch zone, which is important to overcome soil resistance (develop pressure before 8-16 atm by 1 cm). Branching and a high rate of root growth ensure a constant uptake of water and ions.

For stretch zones roots are characteristic increased ID, row activation enzymes(auxin oxidase, polyphenol oxidase, cytochrome oxidase, etc.). As a result of growth by extension, the initial volume of the meristematic cell increases by 10-30 times due to the formation and increase of vacuoles, in which the content of osmotically active substances - ions, OK, sugars, etc. increases.

Some epidermal cells of the root form root hairs length 0.15-8mm. The number of root hairs in corn reaches 420 by 1 cm 2 root surface. They operate on average. 2-3 days and die. In the absence of calcium in the nutrient solution, aeration root hairs are not formed.

Lateral roots laid in pericycle maternal root in the zone takeovers or higher. Its meristematic cells secrete hydrolytic enzymes that dissolve the membranes of the cells of the cortex and rhizoderm, ensuring its release to the outside.

adventitious roots are laid in meristematic or potentially meristematic tissues (cambium, phellogen, medullary rays) of various plant organs (old parts of the root, stems, leaves, etc.).

Root growth depends on the age and type of plant, environmental conditions. Environmental conditions favorable for photosynthesis promote root growth, and vice versa. Shading plants or mowing the aerial part inhibits growth and reduces root mass. Optimal temperature a few for root growth lower than for escape. The ratio of roots to temperature changes in ontogeny. So, the roots of young plants tomatoes grow best at 30°C than at 20 °C, and adults vice versa. At soil drying up before wilting moisture root growth stops. With moderate irrigation, wheat roots are located in the upper layers of the soil, and without watering they penetrate deeper. Optimal soil density for growing roots of corn and other crops 1.1...1.3 g/cm 3 . AT dense soil, the length of cells and the size of the elongation zone decrease due to the formation ethylene, the cost of breathing increases. critical content O 2 in the soil air - about 3-5 % volume. The need for roots in oxygen is greater, the higher the soil temperature. Minimum different oxygen requirements rice and buckwheat, a maximum - tomato, pea, corn. Roots rice have aerenchyma. In plants of winter rye and wheat on crops flooded with melt water in spring, the leaves, while in the air, can also supply oxygen to the roots for a short time. For the growth of the roots of most plants, the optimal pH 5-6.

Hormonal regulation of root growth . Root growth requires low (10 -11...10 -10 M) auxin concentrations. An increase in the flow of auxin from the shoot inhibits the growth of the root in length, which is also explained by the induction of ethylene synthesis. Gibberellins do not affect root growth, but cytokinins in high concentrations inhibit it. ABK, formed by the root cap, slows down the growth of the root in length, the root tip inhibits the formation of lateral roots, so removing it stimulates their formation. Apparently, this is the result of the action of cytokinins inhibiting rhizogenesis, which are formed in the root apex.

The initiation of lateral roots begins at such a distance from the root apex that a certain ratio of cytokinin and auxin (an activator of rhizogenesis) coming from the stem is provided. Ethylene promotes the establishment of lateral roots closer to the root tip, and the treatment of plants with it causes the massive formation of adventitious roots. On dense soils, the mechanical resistance of the environment leads to the synthesis of "stress" ethylene in the roots. In this case, instead of elongation, a thickening occurs in the cell elongation zone, which facilitates the separation of soil particles and the subsequent elongation of the root. The decrease in root increments can also be associated with the accumulation of phenolic inhibitors in cells and further lignification of cell walls.

Signs of deficiency and excess of substances in plants

Lack and excess of nitrogen

Lack of nitrogen It is most pronounced on older lower leaves from the very beginning of the growing season of indicator plants: strawberries, apple trees, potatoes, tomatoes.

The leaves become smaller in pome crops, they become narrow, losing their rich green color. Orange and red dots appear on pale green young leaves. Leaves turn yellow and fall prematurely. Roses in the spring are especially sensitive to a lack of nitrogen. There is a weak growth of shoots, the flowering of the plant weakens, the wood of the stems does not ripen well. Strawberries have poor whisker formation.

Nitrogen starvation of plants can increase due to increased acidity of the soil and turfing of its surface under fruit trees.

With excess nitrogen the foliage becomes dark green in color. Plants begin to grow violently, but their stems are soft, few flowers form. Plants are easily affected by fungal diseases. An excess of nitrogen fertilizers leads to the development of chlorosis along the edges of the leaves and between the veins, brown necrotic spots appear on them, the ends of the leaves curl.

Phosphorus deficiency and excess

Phosphorus deficiency It is most pronounced on the older lower leaves of indicator plants, such as: peach, apple, strawberry, black currant and tomato.

The leaves are dull dark green, with a red or purple or bronze sheen. Red and purple-brown stripes and spots may appear on the edges of the leaves, as well as near the petioles and veins. Stems, petioles and leaf veins also acquire a purple color.

The leaves become smaller, become narrow, move away from the shoots at an acute angle, dry out and fall off. Leaves fall early, drying leaves darken, sometimes even turn black. Flowering and fruit ripening is delayed. Plants lose their decorative effect.

The growth of the shoots slows down, they bend and weaken, often the shoots are blind. The root system develops poorly, root growth is delayed. In general, winter hardiness decreases in plants.

Organic fertilizers have a beneficial effect on the composition of the soil, improve its permeability to water and air, and stabilize the soil structure. In the process of decomposition in the ground, organic fertilizers form a layer of soil humus, which increases its fertility.

Symptoms of phosphorus starvation of plants most often are observed on acidic light soils with a low content of organic matter.

Excess phosphorus leads to soil salinization and manganese deficiency. In addition, the plant loses the ability to absorb iron and copper, as a result, the metabolism is disturbed. In plants that have received an excess of phosphorus, the leaves become smaller, grow dull, curl up and become covered with growths. Plant stems harden.

Deficiency and excess of potassium

Sign of potassium deficiency more pronounced in the middle of the growing season on the older lower leaves of indicator plants: strawberries, raspberries, currants, tomatoes and beets.

Symptoms of potassium deficiency are first manifested by blanching of the leaves. The color of the leaves is dull, bluish-green. There is an uneven growth of leaf blades, the leaves become wrinkled, sometimes leaf curl is noted. The edges of the leaves go down. The leaves turn yellow starting at the top, but the veins remain green. Gradually, the leaves turn completely yellow and acquire a reddish-purple color.

This phenomenon is noted in blackcurrant, whose leaves, with a lack of potassium, become purple with a marginal burn. The marginal “burn” along the edges of the leaves is a rim of drying tissue, then the leaves dry out.

The plant becomes stunted with short internodes, the shoots grow thin and weak.

Young rose leaves turn reddish, with brown edges. Plant flowers are small. This phenomenon is often observed in roses growing on sandy and peaty soils, where roses lack potassium. First, the lower leaves die off, then the process passes to young leaves, they turn black. With the continuation of the process, the stems of roses also die.

signs potassium starvation They can manifest themselves most clearly on soils with a high level of acidity, as well as on those soils to which excessive doses of calcium and magnesium were added.

Excess potassium causes a delay in the development of the plant. The leaves of a plant overfed with potassium acquire a light green color, spots appear on them. First, the growth of the leaves slows down, then they wither and fall off.

Deficiency and excess of calcium

Calcium is needed by plants for the normal development of the aerial part and the growth of roots; in nature, it is found in the form of limestone, chalk and other compounds. Sign of calcium deficiency it is most pronounced on older lower leaves, at the beginning of the growing season on young tissues, on the tops of the shoots of indicator plants, such as: strawberries, gooseberries, currants, cucumbers and cabbage.

The lack of calcium is expressed in a change in the color of young leaves - they turn white and twist up with a hook. Sometimes the leaves are torn.

Stems and leaves are weakened, growth points, peduncles and tops of shoots may die off, leaves and ovaries fall off. The shoots themselves thicken, but in general, the growth of the plant and the formation of new buds slow down. The root system develops poorly, root growth is delayed.

Symptoms of calcium deficiency may appear on soils where there is an excess of potassium.

With excess calcium the shell of nuts and pits of cherries and plums thickens, the leaves may turn yellow, because with an excess of calcium, the plant cannot but absorb iron. These signs are sometimes appear on potassium-poor soils.

Deficiency and excess of iron

For iron deficiency indicate yellowing and partial or complete discoloration of the leaves (chlorosis). However, sometimes pale leaves indicate excess calcium in the soil.

Yellowing of the leaves begins with their edges, young leaves suffer more than others. But around the veins there is still a narrow green stripe. As chlorosis progresses, small veins also become discolored. Then the leaf becomes almost white or acquires a white-cream color. Then the edges of the leaves die off, then the leaf tissues die off completely and they fall off prematurely.

In plants weakened by chlorosis, growth slows down, the tops of trees can dry out, fruits become smaller, and the yield is sharply reduced.

Very often, plants experience a lack of iron in neutral, alkaline and calcium-rich soils. This also happens with excessive liming of the soil when the iron contained in the soil is bound, which can cause chlorosis.

Deficiency and excess of magnesium

Magnesium deficiency it is most pronounced on older lower leaves, more often in the middle of the growing season, especially during drought on indicator plants: potatoes and tomatoes. It is expressed in the development of interveinal chlorosis of leaves, their color becomes similar to a "herringbone". First, discolored spots appear on old leaves, and then on young ones in mid-summer.

Leaves turn yellow, red, or purple as dead dark red areas appear between the veins and dying areas of reddish yellow. But the edges of the leaves and veins remain green for some time. They begin to fall off ahead of time, and early leaf fall begins from the bottom of the plant. Sometimes, due to a lack of magnesium, a pattern appears on the leaves that is similar to the symptoms of mosaic plant disease. The edges of gooseberry leaves turn red in stripes. Often a lack of magnesium leads to a decrease in winter hardiness and freezing of plants.

The most obvious symptoms of magnesium deficiency are on light acidic soils, especially in roses growing in acidic soils. Often lack of magnesium increase the constant application of potash fertilizers. If magnesium compounds in the soil in excess, then the roots of plants do not absorb potassium well.

Lack and excess of boron

Boron boosts the growth of pollen, affects the development of ovaries, seeds and fruits. Sufficient boron content in plant nutrition promotes the influx of sugars to plant growth points, flowers, roots and ovaries.

Signs of a Boron Deficiency most often appear on younger parts of indicator plants, tomatoes, beets. The symptoms are especially pronounced during drought.

Lack of boron affects the growing point of young shoots. With prolonged boron starvation, it dies off. Often there is a slowdown in the development of apical buds with increased development of the lateral ones.

Chlorosis of young leaves develops: light green leaves become smaller, their edges are bent upwards and the leaves are curled. The veins of young leaves turn yellow. Later, marginal and apical necrosis appears on such leaves.

With a lack of boron, the growth of the whole plant is suppressed. On the shoots, small areas of the bark die off, the tops of the shoots can die off (drying). There is a weak flowering and fruit set, which acquire an ugly shape.

The introduction of organic fertilizers increases the content of nutrients in the soil, contributes to the regulation of biological processes in it and activates the activity of soil microorganisms.

The tissues of pome fruits acquire the cork structure. On cauliflower, vitreous heads appear, and on beets, the core rots.

Most often, boron starvation of plants occurs on calcareous soils.

Excess application of boron-containing fertilizers accelerates the ripening of fruits, but at the same time their keeping quality suffers.

Deficiency and excess of manganese

Manganese Deficiency Signs in the soil, they first of all appear on the upper leaves, in their bases of indicator plants: potatoes, cabbage and beets.

White, light green, red spots appear in the same way as with magnesium starvation, but not on the lower, but on the upper, young leaves.

Affected plants develop interveinal chlorosis, the leaves turn yellow between the veins from the edge to the center, forming patches in the form of a tongue. In this case, the leaf veins can remain green for a long time, a green rim forms around the veins. Sometimes a lack of manganese causes brown leaf spot.

With an excess of manganese, iron passes into the oxide form, which is a poison for the plant. To avoid such problems, it is necessary to add four times more iron than manganese. It is this ratio that is beneficial for the plant.

With an excess of magnesium the plant shows signs of calcium deficiency.

Deficiency and excess of copper

Signs of Copper Deficiency are most pronounced on the younger parts of indicator plants - lettuce and spinach. These signs are especially pronounced during drought.

In plants, growth retardation is observed, the apical bud dies off, while the lateral buds awaken at the same time. Then rosettes of small leaves appear on the tops of the shoots.

The tips of the leaves turn white, the leaves themselves become variegated. Sluggish and ugly, they become pale green with brown spots, but no yellowing. The leaf veins stand out sharply against this background. Young leaves lose turgor and wither.

If present in the soil excess copper plants often suffer from iron deficiency.

Deficiency and excess of molybdenum

More often than others lack of molybdenum observed in cauliflower, which is grown on acidic sandy (rarely clay) soils. This symptom manifests itself brighter if physiologically acidic fertilizers are used. Therefore, it is not recommended to use excessively acidic peat for growing seedlings.

Starvation symptoms are manifested in the death of the growing point, as well as in the abscission of buds and flowers. Leaf blades cannot develop to the end, the cauliflower head is practically not tied. Old leaves take on a color, as with chlorosis. In the later stages of development, a lack of molybdenum in cauliflower causes deformation of young leaves. The resistance of early varieties to this problem is much weaker compared to late varieties.

Most often, the lack of molybdenum manifests itself on waterlogged soils, in a cold or dry period, with an excess of nitrogen.

Too much molybdenum leads to a violation of the absorption of copper.

Lack and excess of sulfur

Sulfur affects the redox processes in plant tissues, contributing to the dissolution of mineral compounds from the soil.

With a lack of sulfur the leaves become light green in color, and the veins on the leaves become even lighter. Then red spots of dying tissues appear on them.

With excess sulfur leaves gradually turn yellow from the edges and shrivel, tucking inward. Then they turn brown and die. Sometimes the leaves do not take on yellow, but a lilac-brown hue.

Zinc deficiency and excess

Signs of a zinc deficiency usually appear on old leaves (especially in spring) of indicator plants: tomatoes, pumpkin and beans.

Symptoms first appear on the leaves, which are small, wrinkled, narrow, and mottled due to interveinal chlorosis. The green color remains only along the veins. Often, dead areas appear on the leaf along the edges and between the veins.

Usually zinc deficiency appears on soils rich in nitrogen.

Signs of high zinc content are watery transparent spots on the lower leaves of plants along the main vein. There are outgrowths of irregular shape on the leaf blade, after a while tissue necrosis occurs and the leaves fall off.

SIGNS OF PLANTS NUTRITION DEFICIENCY With a lack of nitrogen, the leaves become shallower, the loss of intense green color, yellowing, the appearance of orange and red hues on the leaf plate, early leaf fall. Growth is inhibited, flowering is weak. Strawberries have poor mustache formation.