The role of sodium in plant life

Sodium regulates the transport of carbohydrates in the plant. A good supply of sodium to plants increases their winter hardiness. With its deficiency, the formation of chlorophyll slows down.

The body of an animal contains approximately 0.1% sodium (by mass).

Sodium is distributed throughout the body. In the human body, sodium is found in red blood cells, blood serum, digestive juices, muscles, in all internal organs, and skin. 40% of sodium is found in bone tissue.

Together with potassium, sodium creates a transmembrane potential of the cell and ensures the excitability of the cell membrane. It is also part of the sodium-potassium pump, a special protein (pore complex) that penetrates the entire thickness of the membrane. The extracellular concentration of Na + ions is always higher than the intracellular one, due to which the concentration gradient of these ions is directed inside the cell, providing active transport of substances into the cell. Sodium maintains the acid-base balance in
body, regulates blood pressure, the functioning of nerves and muscles, the absorption of glucose by cells, the formation of glycogen, protein synthesis, affects the condition of the mucous membranes of the vital organs of the digestive tract. Sodium metabolism is under the control of the thyroid gland.

Its deficiency leads to headaches, weakening of memory, loss of appetite, increased acidity of gastric juice, problems with the bladder, fatigue may occur.

Excess sodium leads to water retention in the body (edema), hypertension, and heart disease.

Salt. All salty foods. Seafood. Vegetables and greens: cabbage, mint, dill, parsley, carrots, onions, lettuce, peppers, asparagus, horseradish, garlic. Fruits and berries: black currants, cranberries, lemons. Animal products: sausage, lard, salted fish, caviar, cheese.

NaCl

NaHCO3- sodium bicarbonate, baking soda.

Do you know that…

Sodium was discovered in 1807 by the English chemist and physicist G. Davy and received its name from Arabic. natron or natrun- detergent - on the use of natural soda and caustic soda for the manufacture of soap.

The number of sodium atoms in the human body is 2.8 x 10 24, and in one human cell - 2.8 x 10 10.

The daily intake of sodium in the body with food is on average 4.4 g.

In medicine, sodium chloride is used as an isotonic 0.9% solution for dehydration. Sodium is part of many drugs, including antibiotics, vikasol, a synthetic derivative of vitamin K.

Calcium

The role of calcium in plant life

The calcium content in plants is on average 0.3% (by weight). Pectins (calcium and magnesium salts of galacturonic acid) are part of the cell walls and intercellular substance of higher and lower plants. Calcium is used as a building material for the median lamina and is also a component of the "external skeleton" of algae; increases the strength of plant tissues and helps to increase the endurance of plants.

Lack of Ca causes swelling of pectin substances, sliming of cell walls and rotting of plants; the root system suffers, whitening of the tops of plants and young leaves occurs. The newly formed leaves are small, twisted, with irregularly shaped edges, light yellow spots appear on the plate, the edges of the leaves are bent down. With a strong calcium deficiency, the top of the shoot dies.

If there is a high content of calcium in the soil, then indicator plants grow well in these areas: Venus slipper, sunflower, steppe aster, pella fern, orchid, mordovnik, toadflax, large-flowered foxglove, mountain cutweed, etc.

Role in the life of animals and humans

In the body of an animal, on average, from 1.9% to 2.5% calcium (by weight). Calcium is a material for building bone skeletons. Calcium carbonate CaCO 3 is part of corals, mollusk shells, shells sea ​​urchins and skeletons of microorganisms.

In the human body, 98-99% of calcium is found in the bones of the skeleton, which act as a "depot" of calcium; calcium ions are present in all tissues and body fluids: 1 g in blood plasma, 6–8 g in soft tissues. With a human weight of 70 kg, the Ca content in the body is 1700 g, with 80% calcium phosphate Ca 3 (PO 4) 2 and 13% calcium carbonate CaCO 3 .

Calcium is necessary for the processes of hematopoiesis and blood coagulation, for regulating the work of the heart, muscle contraction, metabolism, reducing vascular permeability, for normal growth of bones (skeleton, teeth). Calcium compounds have a beneficial effect on the state of the nervous system, the conduction of nerve impulses, have an anti-inflammatory effect, provide cell membrane permeability, and activate certain enzymes. Calcium metabolism is regulated in humans and animals by calcitonin, a hormone thyroid gland, parathyroid hormone - a parathyroid hormone and calciferols - a vitamin D group. It must be remembered that the body absorbs calcium only in the presence of fats: for every 0.06 g of calcium, 1 g of fat is needed. Calcium is excreted from the body through the intestines and kidneys.

Lack of calcium leads to osteoporosis, disorders in the musculoskeletal, nervous systems, insufficient blood clotting.

The main sources of entry into the body

Vegetables and grains: peas, lentils, soybeans, beans, beans, spinach, carrots, turnips, young dandelion leaves, celery, asparagus, cabbage, beets, potatoes, cucumbers, lettuce, onions, wheat grains, rye bread, oatmeal. Fruits and berries: apples, cherries, gooseberries, strawberries, apricots, currants, blackberries, oranges, pineapples, peaches, grapes. Almond. Dairy products: cottage cheese, sour cream, kefir.

Most Common Connections

CaCO3- calcium carbonate, chalk, marble, limestone.
Ca(OH) 2- calcium hydroxide, slaked lime (fluff).
CaO- calcium oxide, quicklime (boiling).
CaOCl 2- mixed salt of hydrochloric and hypochlorous acids, bleach (bleach).
CaSO4 X 2H2O- dihydrate calcium sulfate, gypsum.

Do you know that…

Calcium was discovered by the English chemist H. Dani in 1808 during the electrolysis of wet slaked lime Ca(OH) 2 . Its name comes from lat. calcis(genus case lat. calx- stone, limestone) according to its content in limestone.

The number of calcium atoms in the human body is 1.6 x 10 25, and in one cell 1.6 x 10 11.

The daily intake of calcium from food and water is 500-1500 mg.

Calcareous skeletons of coral polyps, consisting of calcium carbonate, form reefs and atolls, coral islands in tropical seas. From the skeletons of coral polyps, which have been dying off for many millennia, limestone, chalk and marble have formed, which are used as building material.

There are plants - calcephiles (from the Greek. fileo- I love), which grow mainly on alkaline soils rich in calcium, as well as in places where limestone, chalk (forest anemone, six-petal meadowsweet, European larch, etc.) come out.

There are plants - calcephobes (from the Greek. phobos- fear), which avoid limestone soils, because. the presence of calcium ions inhibits their growth (peat mosses, some cereals).

Sulfur

The role of sulfur in the life of plants, microorganisms

The sulfur content in plants is on average 0.05% (by weight). Sulfur is a constituent of amino acids (cystine, cysteine, methionine). Plants obtain sulfur from the soil from soluble sulfates, and putrefactive bacteria convert the sulfur of proteins into hydrogen sulfide H 2 S (hence the disgusting smell of decay). But most of the hydrogen sulfide is formed during the reduction of sulfates by sulfate-reducing bacteria. This H 2 S is oxidized by phototrophic bacteria in the absence of molecular oxygen to sulfur and sulfates, and in the presence of O 2 it is oxidized to sulfates by aerobic sulfur bacteria.

In many bacteria, sulfur is temporarily stored in the form of globules. Its amount depends on the content of hydrogen sulfide: with its deficiency, sulfur is oxidized to sulfuric acid.

2H 2 S + O 2 ––> 2H 2 O + 2S + energy

2S + 3O 2 + 2H 2 O -–> 2H 2 SO 4 + energy

In reservoirs, the water of which contains hydrogen sulfide, colorless sulfur bacteria begiatoa and thiothrix live. They don't need organic food. For chemosynthesis, they use hydrogen sulfide: as a result of reactions between H 2 S, CO 2 and O 2, carbohydrates and elemental sulfur are formed.

Most sulfur is not absorbed by plants, but helps them absorb phosphorus. Lack of sulfur reduces the intensity of photosynthesis. Astragalus is an indicator of high sulfur content in the soil.

Role in the life of animals and humans

The body of an animal contains 0.25% sulfur (by mass). The simplest planktonic radiolarians have a mineral skeleton of strontium sulfate, which provides not only protection, but also “floating” in the water column.

In the human body, sulfur contains 400–700 ppm by weight. Sulfur is a part of proteins and amino acids, enzymes and vitamins. It is especially important for the synthesis of proteins in the skin, nails and hair. Sulfur is a component of active substances: vitamins and hormones (for example, insulin). It is involved in redox processes, energy metabolism and detoxification reactions, activates enzymes.

With a lack of sulfur, the skin undergoes inflammatory diseases observed fragility of bones and hair loss.

Among sulfur compounds, hydrogen sulfide is considered especially dangerous - a gas that has not only a pungent odor, but also great toxicity. AT pure it kills a person instantly. The danger is great even with an insignificant (about 0.01%) content of hydrogen sulfide in the air. Hydrogen sulfide is dangerous because, accumulating in the body, it combines with iron, which is part of hemoglobin, which can lead to severe oxygen starvation and death.

The main sources of entry into the body

Vegetable products: nuts, legumes, cabbage, horseradish, garlic, pumpkin, figs, gooseberries, plums, grapes. Animal products: meat, eggs, cheese, milk.

Most Common Connections

H 2 S- hydrogen sulfide.
Na 2 S- sodium sulfide.

Do you know that…

Sulfur has been known since the 1st century. BC. The name comes from the ancient Hindu sira- light yellow, the color of natural sulfur; Latin name from Sanskrit. solvery- combustible powder.

The number of sulfur atoms in the human body is 3.3 x 10 24, and in one cell - 2.4 x 10 10.

Hydrogen sulfide H 2 S is a poisonous, stinking gas used in the chemical industry, as well as as a remedy (sulphurous baths). Sulfur is a component of medicines, including antibiotics, which can suppress the activity of microbes. Finely dispersed sulfur is the basis of ointments for the treatment of fungal skin diseases.

Natural sulfides form the basis of ores of non-ferrous and rare metals and are widely used in metallurgy. Sulfides of alkali and alkaline earth metals Na 2 S, CaS, BaS are used in the leather industry.

Chlorine

The role of chlorine in the life of plants, microorganisms

The content of chlorine in the body of plants is approximately 0.1% (by mass). It is one of the main elements of the water-salt metabolism of all living organisms. Some plants (halophytes) are not only able to grow on saline soils with a high content of table salt (NaCl), but also accumulate chlorides. These include solyanka, soleros, sveda, tamarix, etc. Chlorine ions Cl - participate in energy metabolism, have a positive effect on the absorption of oxygen by roots. In plants, chlorine is involved in oxidative reactions and photosynthesis.

Halophilic microorganisms live in an environment with NaCl concentration up to 32% - in saline water bodies and saline soils. It's the bacteria of the genera Paracoccus, Pseudomonas, Vibrion and some others. They need high concentrations of NaCl to maintain the structural integrity of the cytoplasmic membrane and the functioning of enzyme systems associated with it.

Role in the life of animals and humans

The body of an animal contains from 0.08 to 0.2% chlorine (by mass). Negatively charged chloride ions, which predominate in the body of animals, play a huge role in water-salt metabolism. In conditions of high salinity, with a salt content in water of at least 3%, halophytes live: radiolarians, reef-forming corals, inhabitants of coral reefs and mangroves, most echinoderms, cephalopods, and many crustaceans. Some rotifers, crustacean Artemia salina, mosquito larva Aedes togoi and some others.

Human muscle tissue contains 0.20-0.52% chlorine, bone - 0.09%, blood - 2.89 g / l. In the body of an adult, about 95 g of chlorine. Every day with food a person receives 3-6 g of chlorine. The main form of its intake into the body is sodium chloride. It stimulates metabolism and hair growth. Chlorine determines the physicochemical processes in the tissues of the body, is involved in maintaining the acid-base balance in tissues (osmoregulation). Chlorine is the main osmotically active substance of blood, lymph and other body fluids.

Hydrochloric acid, which is part of the gastric juice, plays a special role in digestion, providing activation of the pepsin enzyme, and has a bactericidal effect.

The presence of about 0.0001% chlorine in the air irritates the mucous membranes. Constant stay in such an atmosphere can lead to bronchial disease, a sharp deterioration in well-being. According to existing sanitary standards the content of chlorine in the air of working premises should not exceed 0.001 mg / l, i.e. 0.00003%. The content of chlorine in the air in the amount of 0.1% causes acute poisoning, the first sign of which is bouts of severe coughing. In case of chlorine poisoning, absolute rest is necessary, it is useful to inhale oxygen or ammonia (ammonia), or alcohol vapor with ether.

The main sources of entry into the body

Sodium chloride is table salt. Salty foods. Every day a person should consume about 20 g of table salt.

Most Common Connections

NaCl- sodium chloride, table salt.
HCl- hydrochloric acid, hydrochloric acid.
HgCl 2- mercury chloride (II), sublimate.

Do you know that…

Chlorine was first obtained by the Swedish chemist K. Scheele in the interaction of hydrochloric acid with pyrolusite MnO 2 x H 2 O. The name comes from the Greek. cloros- yellow-green color of fading foliage - according to the color of chlorine gas.

Chlorine compounds, primarily common salt NaCl, have been known to mankind since prehistoric times. The alchemists knew hydrochloric acid HCl and its mixture with nitric acid HNO 3 - aqua regia.

The number of chlorine atoms in the human body is 1.8 x 10 24, and in one cell - 1.8 x 10 10.

In small doses, poisonous chlorine can sometimes serve as an antidote. So, victims of hydrogen sulfide are given to sniff unstable bleach. Interacting, two poisons are mutually neutralized.

Chlorination of tap water destroys pathogenic bacteria.

There are aquatic organisms - halophobes that do not tolerate high salinity values ​​and live only in fresh (salinity not higher than 0.05%) or slightly saline (up to 0.5%) water bodies. These are many algae, protozoa, some sponges and coelenterates (hydra), most leeches, many gastropods and bivalves, most aquatic insects and freshwater fish, all amphibians.

HgCl 2 - sublimate - a very strong poison. Its dilute solutions (1: 1000) are used in medicine as a disinfectant.

To be continued

Water in plant life plays a huge role, it is an integral part of every plant, every organ. The percentage of water in the plant organism:

• protoplasm contains about 80% water,
• in cell sap - 96-98% water,
• in the shells of plant cells up to 50% water.
• in the leaves, the water content reaches 80-90%.

A large percentage of water is found in juicy fruits:

• c - up to 98%,
• c - 94%,
• c - 92%,
• c - 77%.

Juicy fruits contain a large percentage of water.

Water is the main solvent

A high water content in plant tissues is necessary for active synthetic activity. Water is the main solvent, and with its participation, the plant receives dissolved in water nutrients through the roots and their movement from one cell to another.

Water in the interaction of plants with the environment

Thanks to water, the plant interacts with environment . AT photosynthesis process water is directly involved in the formation carbohydrates. Out of 1000 parts of water passing through the plant, only 2-3 parts are used in the process of photosynthesis for the formation of carbohydrates, and 997-998 parts of water pass through the plant to maintain its tissues in a state of saturation and to compensate for the evaporated water. A large leaf surface of plants leads to the waste of a huge amount of water: in one hour, plants consume up to 80-90% of the water they contain. The degree of their opening depends on the amount of water in the guard cells of the stomata; with a high content of it, the stomata are open, and carbon dioxide enters the plant through them.

Water consumption by plants

Various plants contain different amounts water, it changes both during the day and during the growing season. By the end of the growing season, the water content decreases.
Water consumption by plants. Of the higher plants, very few representatives of the desert flora can withstand dehydration, (more:) while dry seeds, some lichens and can remain viable even with a low water content. AT various conditions Plants need different amounts of water to grow. In a dry and hot climate, plants spend 2-3 times more water during the growing season than in a temperate climate.

The state of water in plants

water in plants happens in two states- in free and bound. bound by water consider water, which is retained by hydrophilic colloids of protoplasm and active substances. Bound water loses its solvent properties and does not take an active part in the transformation and movement of substances throughout the plant. Role bound water lies in the fact that it prevents the micelles from sticking together and imparts structural stability to the hydrophilic colloids of the protoplasm. The amount of bound water in a plant is not constant, in young plants there is more bound water than in old ones. free water in a plant - the environment in which all the processes of its vital activity take place. A large amount of free water is evaporated by the plant. Such a division of water into free and bound is conditional, since all the water present in cells is associated with substances that make up the protoplasm, cell sap and membrane. These forms of water differ only in the nature and strength of bonds. Biologists have conducted a number of experiments with heavy water containing O 18 . In young bean plants, immersed in heavy water by their roots, there was a rapid change of part of the tissue water to water containing O 18 .
Bean plant bush in bloom. In the tissues of the leaves and roots, which have a rapid metabolism, equilibrium with the external solution was reached after 15–20 minutes, and slightly more than half of the water was exchanged. The water in the stem was replaced by 90%. When the leaves withered, the cell sap lost water the fastest, the cytoplasm water was retained much stronger, and the water that was part of the organelles was lost the least. Based on these experiments, it was concluded that the plant has difficult and easily exchangeable water.

Lecture 2. Water in plants.

Water is an integral part of both the plants themselves and their fruits and seeds. In a living plant, water makes up to 95% of its mass. But this is very little compared to how much the plant spends until it grows and produces a crop.
The need for water various plants, in order to carry out its development cycle, for example, for the conditions of Uzbekistan, only for evaporation (transpiration) by the plants themselves and evaporation from the soil surface in comparison with the ground mass, hundreds of times more than the weight of water contained in an adult plant and its fruits.

Why do plants need this water?

What function does it perform?

Why do plants need so much water?

Well, let's start with the fact that plants "want" not only to drink, but also to eat. So you need to somehow deliver nutrients through the trunks and branches to the leaves. These nutrients, sucked in by the roots along with soil moisture, pre-prepared in the roots in the form of semi-finished products, are delivered through vessels to the leaves - factories. organic matter.
By evaporating water with leaves, the plant cools them, preventing them from overheating, carbon dioxide is obtained from the air (in exchange for evaporated water), which serves as a material for the creation of all organic substances used to build the entire plant.

Figure 2.1. Diagram of the "functioning" of the plant.
(taken from The Life of the Green Plant).
A Galston, P. Davis, R. Satter).

Scientists who thoroughly studied the needs of plants in water were largely discouraged by the variability of the so-called transpiration coefficients, which show the ratio of water costs to produce a unit weight of dry plant mass even in the same plants (not to mention their difference in moisture-loving and drought-resistant vegetation).
Depending on the growing conditions, the cost of water per unit of crop fluctuates very strongly. It has been noticed that when soils are poor in nutrients, the plant evaporates more water than on those rich in them.

Plants that have plenty of moisture available to them good quality, "with pleasure" they spend it, violently developing the vegetative mass, but they are not "in a hurry" to bear fruit. In such cases, the plants are said to "fatten".

Plants that are in conditions of limited moisture reserves "behave more restrained." They spend less moisture, develop a moderate vegetative mass and enter the flowering and fruiting phases faster.

But plants that are severely restrained in water not only do not develop a vegetative mass and do not produce fruits, but they can simply die.

Plants commonly grown in our fields with existing tillage systems , are not able to go deep for water, like wild (and even cultivated) desert plants on soils untouched by man.

It is important for us to provide conditions in order to obtain sustainable harvests not only in years with normal rainfall, but also in dry ones. Therefore, all the actions of the farmer, contributing to the accumulation and preservation of moisture in the root layer of the soil, are rewarded a hundredfold with plants.

In almost all plants, the critical phase of development (when drought has the most harmful effect on them) is the period of flowering and fruit set. As for the development of perennial grasses used for animal feed in fresh form or in the form of hay, their most vulnerable, in terms of moisture, are post-harvest periods.

During these critical periods, it is desirable that the moisture content of the root layer of the soil does not fall below certain limits, which are not so easy to determine even using scientific concepts but we'll still try.

Despite the fact that many processes of supplying plants with water are very similar in different climatic zones, nevertheless, depending on the properties of the soil, the properties of soil-forming rocks, the presence of soil moistening with groundwater, the degree of their salinity, the slopes of the terrain, there are big differences in the methods of conservation soil moisture and ways to replenish it.

General seasonal need of plants for water and features of different phases of their development.

The fact that the required amount of irrigation is directly related to the climate, probably no one doubts ...
Let's take it in order, let's start with the question - how much water should be supplied to the field, and in what time frame, in order to get the expected harvest. First of all, let's look at Fig. 2.1, which shows the average monthly climatic characteristics of the desert zone of Uzbekistan. (In agro-climatic reference books, you can always find these characteristics for your area, and the evaporation (Eo) from the water surface can be calculated using a simple formula, if you do not find it ready-made in the same reference book).

Rice. 2.1. Climatic characteristics and water balance deficit.
t - air temperature, in degrees Celsius;
a - relative humidity in%;
Os - atmospheric precipitation, mm.
Eo - evaporation from the water surface, Eo \u003d 0.00144 * (25 - t) 2 * (100 - a);
D \u003d Eo - Os - water balance deficit (in the figure it is shaded in yellow during the growing season).

This figure shows the course of average monthly air temperatures, the amount of atmospheric precipitation, relative air humidity, calculated indicators of evaporation and humidity deficits. The area of ​​the figure filled with yellow is the deficit of the growing season (in this case, IV ... IX months). But each culture has its own sowing dates, its own growing season, and therefore the need for water for irrigation will depend on these values ​​and will determine its own irrigation period. That is, early-ripening plants may require much less water to complete their seasonal development cycle than late ones, but this does not apply mainly to perennial, tree-shrub plants that consume moisture throughout the growing season.

Although moisture deficits are not yet a need in itself, in any case, the calculated monthly moisture deficits give an approximate idea of ​​which months and how much evaporation exceeds precipitation, which is a lot in order to understand how much irrigation is needed, or you can do without it. .

Scientists have found that to calculate the total water consumption, one can use empirical equations that relate the moisture deficit to the actual moisture consumption of an irrigated crop (if one determines the coefficients that allow one to find a correspondence between these indicators).
One of the simplest dependencies looks like this:

Мveg \u003d 10 * Kk * D

(2.1)

Where Мweg is the irrigation rate of the growing season of the crop under consideration, m3/ha;
Kk is an empirical coefficient of culture, which also depends on plant species applied agricultural technology and growing season;
D is the total moisture deficit during the growing season of the cultivated crop, mm.

On fig. 2.2, as an example, shows the phases of development of cotton, the timing of the start of vegetation, the timing of the start of the irrigation period, the proportion of physical (from the soil surface) evaporation for the central climatic zone of Uzbekistan.

Rice. 2.2, Characteristic periods (development phases) for cotton for the central climatic zone of Uzbekistan.

In order to establish the value of the Kk coefficient, scientists conduct long-term experiments with different variants of irrigation regimes and compare the yields obtained with water costs, and then these costs are compared with actual moisture deficits. These works provide them (scientists) with life-long employment, because over time, plant varieties, agricultural techniques used, and irrigation methods change, and the climate, as you know, is not constant ... so you can study for a long time, one might say - indefinitely. For example, in Figure 2.3 we present the results of summarizing the materials of studying the irrigation regimes of cotton for about 70 years. This includes the results of ~ 270 experiments conducted at more than 13 experimental stations in Uzbekistan. This crop was the most needed for many years, and in Central Asia the most research was carried out on it, well, about ten times more than on alfalfa, wheat and corn!

Consider carefully the three graphs in Figure 2.3. Let's explain a little the essence of the graphs. Here Y is the yield on any plot from the given experiment, and Umax is the maximum yield on the plot with the best water supply in this experiment. All compared results for plots in each experiment, in each year of the study were obtained under the same weather conditions, but for each of the plots in the experiment, the values ​​​​of the ratio of the irrigation rate to the moisture deficit for the growing season (M / D) were different and the yield should have been depend only on the volume of irrigation water.
However, the figures show that a yield close to the maximum (U/Umax = 1) occurs in different experiments with the ratio of the irrigation rate to the moisture deficit during the growing season from 0.15 to 1.2, that is, the difference is almost tenfold! And why this is so is completely incomprehensible to us, since from each series of experiments described in the works of scientists, we specially selected the results of only those where there was the same "background", and only the irrigation rate changed. And this range of data scatter is almost the same, both at close and at deep groundwater! It should also be noted that the maximum yields in the experiments we chose for analysis did not occur, in practice, below 45 ... 50 centners per hectare, and basically these lowest indicators were characteristic of the northern regions of Uzbekistan.
It can be assumed that the harvest, probably, depends not only on the "background" and the volume of water supplied for irrigation, but is also associated with the art of the farmer? Or maybe from the timeliness of the irrigation? How do you think? In any case, this richest material is waiting for its researchers and analysts...

But for the time being, there is nothing left for us to do, how to focus on the "golden mean" of experimental "clouds" of data and take, in this case, the same coefficient in formula 2.1 -
Kk \u003d M / D \u003d 0.4 ... 0.65 (mlower values ​​for close groundwater, and higher values ​​for deep ones). However, for orientation and it's not so bad. Knowing the deficit during the growing season from weather data, it is possible, by multiplying it by the Kk coefficient, to obtain an approximate need for irrigation water. For the middle latitudes of the steppe zone of Uzbekistan, the total deficit for the growing season (IV…IX months) is about 1000 mm. Then the irrigation rate will be from 400 to 650 mm, or in terms of m3/ha - 4000...6500 m3/ha.
Approximately the same amount is required for corn for grain, and one and a half times less is enough for cereals, that is, 3000 ... 4500 m3 / ha. It should be noted that part of this need can be covered by non-vegetation moisture reserves if they can be stored in the soil by proper agricultural practices.

Figure 2.3. Actual data on water consumption for cotton, obtained in the experiments of various scientists. The upper figure collects data obtained at close groundwater, the middle one shows data for the transitional conditions between close and deep groundwater, and the lower one shows data for groundwater below 3 m.
(The points above the Y/Umax = 1 line are conditional, they simply show the number of experiments used in evaluating one or another M/D ratio and plotting).

So far we have been talking about the average long-term climate indicators, but in nature there is no year for year, there are dry years, and there are very rainy ones. Naturally, there is no need to water in a rainy year, but in a dry one it is very necessary. Therefore, irrigation equipment will only be used in selected dry years. But under certain conditions, the stability of the productivity of agricultural production over the years may be more important than some extra costs for organizing irrigation.
Further we (in lecture 9) will tell a little about what else water is spent on in irrigation systems in order to maintain the normal development of cultivated plants in the fields, and "it won't seem enough"!
Below, in Table 3.1, for example, the values ​​of the Kk coefficients for different crops in Uzbekistan are given from the work, which summarized the vast experience of many scientists in Central Asia (Calculated values ​​of irrigation norms for agricultural crops in the Syrdarya and Amudarya river basins. Compiled by: V.R. Schroeder , V.F.Safonov and others). "Taking my hat off" to a great scientist - my mentor V.R. Schroeder, who was the ideologist of this gigantic work, I specially familiarized you with the data, mainly used in its compilation, so that you would be critical of any conclusions that were not your own and on word was not trusted to anyone.

Table 2.1. Values ​​of Kk coefficients for different crops in climatic zones of Uzbekistan.

culture	By climatic zones
	C-1	C-2	C 1	C-2	Yu-1	Yu-2
Cotton		0,60	0,63	0,65	0,68	0,70
Alfalfa and other herbs	0,77	0,81	0,84	0,88	0,92	0,95
Gardens and other plantations	0,53	0,55	0,58	0,60	0,62	0,65
Vineyards	0,44	0,46	0,48	0,50	0,52	0,54
Corn and sorghum for grain	0,62	0,61	0,62	0,59	0,58	0,57
Row crops with repeated			0,66

An acute lack of iron in the plant causes ... leaves.

Cation ... is involved in stomatal movements.

Resistance to lodging in cereals increases ....

Deficiency... causes damage to the terminal meristems.

Nucleic acids contain...

The order of increase in the content of ash in the organs and tissues of plants.

INSUFFICIENCY

MACRO - AND MICROELEMENTS, THEIR SIGNIFICANCE AND SIGNS OF THEM

MINERAL NUTRITION

Establish a correspondence between a group of plants and the minimum water content necessary for life.

WATER ABSORPTION AND TRANSPORT

Water absorption and transport

109. Water makes up an average of __% of the mass of a plant.

110. Plant seeds in the air-dry state contain ...% water.

111. About ....% of the water contained in the plant takes part in biochemical transformations.

1. hygrophytes

2. mesophytes

3. xerophytes

4. hydrophytes

113. The main functions of water in a plant:….

1. maintaining heat balance

2. participation in biochemical reactions

3. ensuring the transport of substances

4. creating immunity

5. providing communication with external environment

114. The main osmotic space of mature plant cells is …..

1. vacuole

2. cell walls

3. cytoplasm

4. apoplast

5. symplast

115. Raising water along a tree trunk provides ....

1. suction action of the roots

2. root pressure

3. water thread continuity

4. osmotic pressure of vacuolar juice

5. features of the structure of conducting beams

116. Products of photosynthesis include... % of water passed through the plant.

5. more than 15

117. Maximum water deficit in plant leaves under normal
conditions observed in....

1. noon

3. in the evening

118. A significant proportion of water due to the swelling of colloids in plants
absorb....

2. meristem

3. parenchyma

5. wood

119. Phenomenon of protoplast detachment from the cell wall in hypertonic
solutions is called ###.

120. The degree of opening of the stomata directly affects... .

1. transpiration

2. absorption of CO 2

3. selection of O 2

4. ion absorption

5. speed of transport of assimilates

121. Cuticular transpiration of adult leaves is ...% of evaporated water.

2. about 50

122. Usually stomata occupy ... % of the entire surface of the leaf.

5. more than 10

123. The greatest resistance to the flow of liquid water in a plant is..

1. root system

2. conducting system of leaves

3. stem vessels

4. mesophyll cell walls

124. The total surface of the roots exceeds the surface of the aboveground organs in
an average of ... times.

125. Sulfur is a part of protein in the form....

1. sulfite (SO 3)

2. sulfate (SO 4)

3. sulfhydryl group

4. disulfide group

2. tree bark
3.stem and root

5. wood

127. Phosphorus is a part of:....

1.carotenoids

2. amino acids

3. nucleotides

4. chlorophyll

5. some vitamins

128. Elements of mineral nutrition in the composition of chlorophyll: ...
1.Mg 2.Cl 3.Fe 4. N 5. Cu

129. The biochemical role of boron is that it... .

1. is an enzyme activator

2. is part of oxidoreductases

3. activates substrates

4. Inhibits a number of enzymes

5. enhances the synthesis of amino acids

1.N2.SЗ.Fe 4. Р 5. Са

1.Ca 2.Mn 3. N 4. P5.Si

132. Deficiency ... leads to the fall of the ovary and stunted growth of pollen
tubes.

1. Ca 2. K Z.Cu 4. B 5. Mo

3.0,0001-0,00001

1.Ca 2. K Z.N 4. Fe 5.Si

135. Plant coenzymes may contain the following elements: ... .

1. K 2. Ca 3. Fe 4. Mn 5. B

1. Ca 2+ 2. M e 2+ Z. Na + 4. K + 5. Cu 2+

137. Outflow of sugars from leaves is prevented by deficiency of elements: ... .

1 .N 2. Ca Z.K 4. B 5.S

138. Sugar beet heart rot is caused by....

1. excess nitrogen

2. lack of nitrogen

3. boron deficiency

4. potassium deficiency

5. Phosphorus deficiency

139. Lack of phosphorus in a plant causes....

1. yellowing of upper leaves

2. chlorosis of all leaves

3. curling leaves from the edges

4. appearance of anthocyanin coloration

5. necrosis of all tissues

140. Potassium is involved in the life of the cell in the role....

1. component of enzymes

2. component of nucleotides

3. intracellular cations

4. Cell wall components

5. components of the extracellular wall

3. browning of the edges

4. mottling
5.twisting

142. Lack of potassium in a plant causes... .

1. the appearance of necrosis from the edges of the leaves

2. leaf scorch

3. yellowing of lower leaves

4. browning of the roots

5. the appearance of anthocyanin coloration on the leaves

143. Plant cell nitrate reductase enzyme contains: ....

1. Fe 2.Mn Z.Mo 4. Mg 5. Ca

144. Nitrogen is assimilated by a plant cell as a result... .

1. interactions of nitrates with carotenoids

2. accepting ammonia ATP

3. Amination of keto acids

4. Amination of sugars

5. Acceptance of nitrates by peptides

Chemical composition and nutrition of plants

Chemical composition of plants and crop quality

The role of individual elements in plant life. Carryover of nutrients with crop yield

The composition of plants includes water and the so-called dry matter, represented by organic and mineral compounds. The ratio between the amount of water and dry matter in plants, their organs and tissues varies widely. Thus, the content of dry matter in the fruits of cucumbers, melons and gourds can be up to 5% of their total mass, in heads of cabbage, radish and turnip roots - 7-10, root crops of table beets, carrots and onion bulbs - 10-15, in vegetative organs most field crops - 15-25, sugar beet roots and potato tubers - 20-25, in grain cereals and legumes - 85-90, oilseeds - 90-95%.

Water

In the tissues of growing vegetative organs of plants, the water content varies from 70 to 95%, and in the storage tissues of seeds and in the cells of mechanical tissues, from 5 to 15%. As plants age, the total supply and relative water content in tissues, especially reproductive organs, decreases.

The functions of water in plants are due to its inherent physical and chemical properties. It has a high specific heat capacity and, thanks to its ability to evaporate at any temperature, protects plants from overheating. Water is an excellent solvent for many compounds; in the aquatic environment, the electrolytic dissociation of these compounds and the assimilation of ions by plants, which contain the necessary elements of mineral nutrition, take place. The high surface tension of water determines its role in the processes of absorption and movement of mineral and organic compounds. The polar properties and structural ordering of water molecules determine the hydration of ions and molecules of low- and high-molecular compounds in plant cells.

Water is not just a filler of plant cells, but also an inseparable part of their structure. The hydration of plant tissue cells determines their turgor (fluid pressure inside the cell on its membrane), is an important factor in the intensity and direction of various physiological and biochemical processes. With the direct participation of water, a huge number of biochemical reactions of synthesis and decomposition of organic compounds in plant organisms take place. Water is of particular importance in energy transformations in plants, primarily in the accumulation of solar energy in the form of chemical compounds during photosynthesis. Water has the ability to transmit the rays of the visible and near-violet part of the light necessary for photosynthesis, but delays certain part infrared thermal radiation.

Dry matter

The dry matter of plants is 90-95% represented by organic compounds - proteins and other nitrogenous substances, carbohydrates (sugars, starch, fiber, pectin substances), fats, the content of which determines the quality of the crop (Table 1).

The collection of dry matter with the commercial part of the harvest of the main agricultural crops can vary over a very wide range - from 15 to 100 centners or more per 1 ha.

Proteins and other nitrogenous compounds.

Proteins - the basis of the life of organisms - play a decisive role in all metabolic processes. Proteins perform structural and catalytic functions, they are also one of the main storage substances of plants. The content of proteins in the vegetative organs of plants is usually 5-20% of their mass, in the seeds of cereals - 6-20%, and in the seeds of legumes and oilseeds - 20-35%.

Proteins have the following fairly stable elemental composition (in%): carbon - 51-55, oxygen - 21-24, nitrogen - 15-18, hydrogen - 6.5-7, sulfur - 0.3-1.5.

Plant proteins are built from 20 amino acids and two amides. Of particular importance is the content in plant proteins of the so-called essential amino acids (valine, leucine and isoleucine, threonine, methionine, histidine, lysine, tryptophan and phenylalanine), which cannot be synthesized in humans and animals. These amino acids humans and animals get only from plant foods. food products and fodder.

Table number 1.
Average chemical composition yield of agricultural plants, in% (according to B.P. Pleshkov)

culture	Water	Squirrels	Crude protein	fats	Dr. carbohydrates	Cellulose	Ash
Wheat (grain)	12	14	16	2,0	65	2,5	1,8
Rye (grain)	14	12	13	2,0	68	2,3	1,6
Oats (grain)	13	11	12	4,2	55	10,0	3,5
Barley (grain)	13	9	10	2,2	65	5,5	3,0
Rice (grain)	11	7	8	0,8	78	0,6	0,5
Corn (grain)	15	9	10	4,7	66	2,0	1,5
Buckwheat (grain)	13	9	11	2,8	62	8,8	2,0
Peas (grain)	13	20	23	1,5	53	5,4	2,5
Beans (grain)	13	18	20	1,2	58	4,0	3,0
Soy (grain)	11	29	34	16,0	27	7,0	3,5
Sunflower (kernels)	8	22	25	50	7	5,0	3,5
Flax (seeds)	8	23	26	35	16	8,0	4,0
Potatoes (tubers)	78	1,3	2,0	0,1	17	0,8	1,0
Sugar beet (roots)	75	1,0	1,6	0,2	19	1,4	0,8
Fodder beet (roots)	87	0,8	1,5	0,1	9	0,9	0,9
Carrots (roots)	86	0,7	1,3	0,2	9	1,1	0,9
Onion	85	2,5	3,0	0,1	8	0,8	0,7
Clover (green mass)	75	3,0	3,6	0,8	10	6,0	3,0
Hedgehog team (green mass)	70	2,1	3,0	1,2	10	10,5	2,9
*Crude protein includes proteins and non-protein nitrogenous substances

Proteins of various agricultural crops are unequal in amino acid composition, solubility and digestibility. Therefore, the quality of crop products is assessed not only by the content, but also by the digestibility, usefulness of proteins based on the study of their fractional and amino acid composition.

Proteins contain the vast majority of nitrogen in seeds (at least 90% of the total amount of nitrogen in them) and vegetative organs of most plants (75-90%). At the same time, in potato tubers, root crops and leafy vegetables, up to half of the total amount of nitrogen falls on the share of nitrogenous non-protein compounds. They are represented in plants by mineral compounds (nitrates, ammonium) and organic compounds (among which free amino acids and amides, which are well absorbed in animals and humans), predominate. A small part of non-protein organic compounds in plants is represented by peptides (constructed from a limited number of amino acid residues and therefore, unlike proteins, having a low molecular weight), as well as purine and pyrimidine bases (which are part of nucleic acids).

To assess the quality of crop products, the “crude protein” indicator is often used, which expresses the sum of all nitrogenous compounds (protein and non-protein compounds). Calculate "crude protein" by multiplying the percentage of total nitrogen in plants by a factor of 6.25 (derived from the average (16%) nitrogen content of protein and non-protein compounds).

The quality of wheat grain is evaluated by the content of raw gluten, the quantity and properties of which determine the baking properties of flour. Raw gluten is a protein clot that remains when the dough mixed with flour is washed with water. Raw gluten contains approximately 2/3 of water and 1/3 of solids, represented primarily by sparingly soluble (alcohol- and alkali-soluble) proteins. Gluten has elasticity, resilience and cohesion, on which the quality of products baked from flour depends. Between the content of "crude protein" in wheat grain and "crude gluten" there is a certain correlation. The amount of crude gluten can be calculated by multiplying the percentage of crude protein in the grain by a factor of 2.12.

Carbohydrates

Carbohydrates in plants are represented by sugars (monosaccharides and oligosaccharides containing 2-3 monosaccharide residues) and polysaccharides (starch, fiber, pectin substances).

The sweet taste of many fruits and berries is associated with their content of glucose and fructose. Glucose in significant quantities (8-15%) is found in grapes, from which it received the name "grape sugar", and accounts for up to half of the total amount of sugars in fruits and berries. Fructose, or "fruit sugar", accumulates in large quantities in stone fruits (6-10%) and is found in honey. It is sweeter than glucose and sucrose. In root crops, the proportion of monosaccharides among sugars is small (up to 1% of their total content).

Sucrose is a disaccharide made up of glucose and fructose. Sucrose is the main storage carbohydrate in sugar beet roots (14-22%) and stem juice sugar cane(11-25%). The purpose of growing these plants is to obtain raw materials for the production of sugar used in human nutrition. It is found in small amounts in all plants, its higher content (4-8%) is found in fruits and berries, as well as carrots, table beets and onions.

Starch is found in small amounts in all green plant organs, but accumulates in tubers, bulbs and seeds as the main storage carbohydrate. in potato tubers early varieties starch content 10-14%, medium and late-ripening - 16-22%. Based on the dry weight of tubers, this is 70-80%. Approximately the same relative content of starch in the seeds of rice and malting barley. In the grain of other cereals, starch is usually 55-70%. There is an inverse relationship between protein and starch content in plants. In protein-rich seeds of leguminous crops, there is less starch than in seeds of cereals; even less starch in oilseeds.

Starch is a carbohydrate that is easily digestible by humans and animals. During enzymatic (under the action of amylase enzymes) and acid hydrolysis, it decomposes to glucose.

Cellulose, or cellulose, is the main component of cell walls (in plants it is associated with lignin, pectins and other compounds). Cotton fiber is 95-98%, bast fibers of flax, hemp, jute are 80-90% fiber. In the seeds of filmy cereals (oats, rice, millet) fiber contains 10-15%, and in the seeds of cereals that do not have films - 2-3%, in the seeds of leguminous crops - 3-5%, in root crops and potato tubers - about 1 %. In the vegetative organs of plants, the fiber content is from 25 to 40% by dry weight.

Cellulose is a high molecular weight polysaccharide from an unbranched chain of glucose residues. Its digestibility is much worse than starch, although glucose is also formed with complete hydrolysis of fiber.

Pectins are high molecular weight polysaccharides found in fruits, roots and plant fibers. In fibrous plants, they fasten individual bundles of fibers together. The property of pectins in the presence of acids and sugars to form jelly or jellies is used in the confectionery industry. The structure of these polysaccharides is based on a chain of polygalacturonic acid residues with methyl groups.

Fats and fat-like substances (lipids) are structural components of the cytoplasm of plant cells, and in oilseeds they play the role of reserve compounds. The amount of structural lipids is usually small - 0.5-1% of the wet weight of plants, but they perform important functions in plant cells, including the regulation of membrane permeability. Oilseeds and soybeans are used to produce vegetable fats called oils.

By chemical structure fats - a mixture of esters of the trihydric alcohol glycerol and high molecular weight fatty acids. In vegetable fats, unsaturated acids are represented by oleic, linoleic and linolenic acids, and saturated acids are palmitic and stearic acids. The composition of fatty acids in vegetable oils determines their properties - consistency, melting point and ability to dry out, rancidity, saponification, as well as their nutritional value. Linoleic and linolenic fatty acid are found only in vegetable oils and are "indispensable" for humans, since they cannot be synthesized in his body. Fats are the most energy-efficient reserve substances - when they are oxidized, twice as much energy is released per unit mass as compared to carbohydrates and proteins.

Lipids also include phosphatides, waxes, carotenoids, stearins, and the fat-soluble vitamins A, D, E, and K.

Depending on the type and nature of the use of products, the value of individual organic compounds may be different. In cereal grains, the main substances that determine the quality of products are proteins and starch. Wheat is high in protein among grain crops, and rice and malting barley are high in starch. When using barley for brewing production, the accumulation of protein degrades the quality of raw materials. Also undesirable is the accumulation of protein and non-protein nitrogenous compounds in sugar beet roots used for sugar production. Leguminous crops and legumes are distinguished by a high content of proteins and a lower content of carbohydrates, the quality of their harvest depends primarily on the amount of protein accumulation. The quality of potato tubers is evaluated by starch content. The purpose of the cultivation of flax, hemp and cotton is to obtain fiber, consisting of fiber. An increased amount of fiber in the green mass and hay of annual and perennial grasses worsens their fodder qualities. Oilseeds are grown for fats - vegetable oils used for both food and industrial purposes. The quality of agricultural products may also depend on the presence of other organic compounds - vitamins, alkaloids, organic acids and pectin substances, essential and mustard oils.

Plant nutrition conditions are important for increasing the gross harvest of the most valuable part of the crop and improving its quality. For example, an increase in nitrogen nutrition increases the relative content of protein in plants, and an increase in the level of phosphorus-potassium nutrition ensures a greater accumulation of carbohydrates - sucrose in sugar beet roots, starch in potato tubers. By creating appropriate nutritional conditions with the help of fertilizers, it is possible to increase the accumulation of the most economically valuable organic compounds in the dry matter of plants.

Elemental composition of plants

The dry matter of plants has on average the following elemental composition (in weight percent); carbon - 45, oxygen - 42, hydrogen - 6.5, nitrogen and ash elements - 6.5. In total, more than 70 elements have been found in plants. At the current level of development of scientific data, about 20 elements (including carbon, oxygen, hydrogen, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, boron, copper, manganese, zinc, molybdenum, vanadium, cobalt and iodine) are considered definitely essential for plants. Without them, the normal course of life processes and the completion of the full cycle of plant development are impossible. With regard to more than 10 elements (including silicon, aluminum, fluorine, lithium, silver, etc.), there is information about their positive effect on the growth and development of plants; these elements are considered conditionally necessary. Obviously, with the improvement of methods of analysis and biological research, the total number of elements in the composition of plants and the list necessary elements will be expanded.

Carbohydrates, fats and other nitrogen-free organic compounds are built from three elements - carbon, oxygen and hydrogen, and nitrogen is also included in the composition of proteins and other nitrogenous organic compounds. These four elements - C, O, H and N are called organogenic, on average they account for about 95% of the dry matter of plants.

When plant material is burned, organogenic elements evaporate in the form of gaseous compounds and water vapor, and numerous “ash” elements remain in the ash mainly in the form of oxides, which account for an average of only about 5% of the dry matter mass.

Nitrogen and ash elements such as phosphorus, sulfur, potassium, calcium, magnesium, sodium, chlorine and iron are found in plants in relatively large quantities (from a few percent to hundredths of a percent of dry matter) and are called macronutrients.

Quantitative differences in the content of macro- and microelements in the dry matter of plants are shown in Table 2.

The relative content of nitrogen and ash elements in plants and their organs can vary widely and is determined by the biological characteristics of the culture, age, and nutritional conditions. The amount of nitrogen in plants is closely correlated with protein content, and it is always more in seeds and young leaves than in the straw of mature crops. The tops of the nitrogen content is higher than in the tubers and root crops. Ash accounts for 2 to 5% of the mass of dry matter in the marketable part of the harvest of the main agricultural crops, in young leaves and straw of cereals, tops of root and tuber crops 6-14%. Leafy vegetables (lettuce, spinach) have the highest ash content (up to 20% or more).

The composition of ash elements in plants also has significant differences (Table 3). In the ashes of seeds of cereals and legumes, the amount of oxides of phosphorus, potassium and magnesium is up to 90%, and phosphorus predominates among them (30-50% of the mass of ash). The share of phosphorus in the ashes of leaves and straw is much less, and potassium and calcium predominate in its composition. The ash of potato tubers, sugar beet roots and other root crops is represented mainly by potassium oxide (40-60% of the mass of ash). Root ash contains a significant amount of sodium, and cereal straw contains silicon. Legumes and plants of the cabbage family are distinguished by a higher sulfur content.

Table number 3.
Approximate content of individual elements in plant ash, in % of its mass

culture	P2O5	K2O	CaO	MgO	SO 4	Na2O	SiO2
Wheat
corn	48	30	3	12	5	2	2
straw	10	30	20	6	3	3	20
Peas
corn	30	40	5	6	10	1	1
straw	8	25	35	8	6	2	10
Potato
tubers	16	60	3	5	6	2	2
haulm	8	30	30	12	8	3	2
Sugar beet
roots	15	40	10	10	6	10	2
haulm	8	30	15	12	5	25	2
Sunflower
seeds	40	25	7	12	3	3	3
stems	3	50	15	7	3	2	6

The composition of plants in relatively large quantities includes silicon, sodium and chlorine, as well as a significant number of so-called ultramicroelements, the content of which is extremely low - from 10 -6 to 10 -8%. The physiological functions and absolute necessity of these elements for plant organisms have not yet been finally established.