The chemical composition of plants. Mineral nutrition. Organic Plant Nutrition

Behind the dark-colored humus compounds of the soil, a certain and strong reputation has long been established in the circles of rural workers as one of the critical factors soil fertility. We have a number of indications for this - direct and indirect - even in the ancient treatises on agriculture of ancient Greek and Roman writers. Modern agronomic science also assigns a very prominent role to this complex complex in the phenomena of soil fertility and ranks it among essential elements soil grading survey.
In the field of studying the significance of humus compounds in the phenomena of soil fertility in general and in the life of cultivated plants in particular, quite extensive material has now been accumulated. However, it should be noted that if the indirect role of these compounds in the processes of interest to us (for example, their favorable effect on the physical and chemical-biological properties of the soil) is covered in sufficient detail and completely, then a very important question about their direct participation in the nutrition processes of cultivated plants is also little understood and often contradictory. Stopping for the time being on this last side of the question that interests us, let us proceed in the following presentation to acquaintance with those moments that can be noted as the most important in the history of this question.
The view of rural workers on the humus substances of the soil as a direct source of plant nutrition has long been based partly on direct observations of the phenomena of frequent coincidence between soil productivity, on the one hand, and its dark color- on the other hand, partly on those provisions that from time to time were put forward on this issue by representatives of agronomic science and plant physiology. Thus, in a number of works dating back to the end of the 18th century, a firm conviction was expressed that not only all other elements, but also carbon, can be delivered to plants directly by soluble humus substances in the soil. Wallerius suggested that soil humus is the main source of food for plants and that all other substances only help to dissolve the "fat" of this humus. Similar views on the importance of humus were held by Hassenfratz, Dundonald, Davy, Berzelius, Schubler and others.
All these judgments found a very favorable ground for themselves in the views on this subject that had been established, one might say, for centuries, on the part of practical workers.
The view of soil humus as the only and direct source of plant nutrition, however, has received a special development since the appearance at the beginning of the 19th century. research by A. Thaer, whose name is usually associated with the creation of the so-called "humus (humus) theory" of nutrition of cultivated plants, which left such a prominent mark in the history of the development of agronomic science. “The beginning most conducive to the formation of plants cultivated by us, from which they live, grow and give seeds for the continuation of their breed, is manure or humus that has come from the decomposition of this” ... “Although nature produces a lot inorganic substances, which revitalize and enhance growth, or excite vital forces, or contribute to the decomposition of humus, but actually only humus or plant and animal manure brought to a decent degree of decomposition provides plants with essential and necessary nutrition for them "..," There is no doubt that plants they can also receive some nutrition from the decomposition of water and from airy substances in the atmosphere, as well as from their mutual mixing. Soil fertility, according to A. Thaer, “completely depends on humus, because, with the exception of water, humus alone delivers nutrition from the soil to plants” ... “As humus is a product of life, it is also a condition thereof. He gives food to organic bodies, without him they would not have a special life; at least this can be said of the most perfect animals and plants. So, death and destruction are necessary for the reproduction of a new life, and the more life, the more the amount of humus increases and the more nutrition begins for the vital organs ... "Under the word nutrients should understand that part of the humus, which can already pass into plants and which is real reason fruitfulness, wealth and strength of the soil ... ”, etc.
These brief extracts from the well-known book by A. Thaer (“The Foundations of Rational Agriculture”), the nature of the views held by the cited author on the question of the role of soil humus compounds in the processes of nutrition of cultivated plants is sufficiently determined. The high authority of A. Thaer's personality contributed to the extremely great popularity of the views he preached.
This was further facilitated by the fact that A. Thaer tried to reduce the entire complex issue of soil fertility to some mathematical schemes, which greatly facilitated the resolution of difficult questions for rural workers about the choice of one or another system of farming, this or that crop rotation, this or that fertilizers, etc., etc. Noting that the plants that follow clover, alfalfa, sainfoin, etc. in the crop rotation grow with much greater success than the same plants sown on some kind of bread, A. Thaer concluded that it was not all cultivated plants deplete the soil with nutrients to the same extent, but that some of them can even enrich it with these substances, leaving, for example, a large amount of root and crop residues, which, after their decomposition, contribute to an increase in humus compounds in the soil. In addition to plants that deplete the soil and enrich it, A. Thaer also introduced the concept of soil-refreshing plants, that is, those that leave as much organic matter in the soil as they consume them during their growth, contributing, as it were, to the “orvegetation” of old reserves humus new. At the same time, A. Thaer, on the basis of a number of considerations and calculations, tried to depict the degree of depletion and enrichment of the soil produced by various plants, a certain number of degrees, assuming that the degree of fertility of a particular soil, as well as the benefits one or another fertilizing material, the fallow state of the field, etc.
So, for example, if the soil has 40 degrees of natural fertility (this number of degrees A. Thaer characterizes the lowest degree of fertility, namely, when the soil, left for a long time without fertilization, produces a crop of "self-friend"), then by means of a fallow the latter is increased by 10 °; if the soil has 50 ° fertility, then the latter increases by 11 °, with 60 ° natural fertility - by 12 °, etc.
From the culture of clover, the fertility of the soil also increases: if the soil has 60 ° of natural fertility, then with this culture it receives another 10 °; if the soil has 72° of natural fertility, then with this culture it receives another 12°; if the soil has 100° of natural fertility, then with this culture it receives another 15°, and so on.
For manure fertilizer, it was calculated that each 1 ton per hectare increases soil fertility by 1°.
Representing more specifically the degree of enrichment and depletion produced in the soil by various plants, we obtain the following table:

By adding up the number of degrees by which some plants increase the fertility of the soil, as well as the number by which other plants introduced into the crop rotation are reduced, it was possible in this way to calculate the profitability or rationality of any crop rotation, etc. By such calculations it was, for example, , determined that
- with a 3-year crop rotation with fallow, fertilized for 9 years once with 20 trucks of manure, soil fertility decreases by 17.24 °;
- with a 4-year crop rotation, fruitful with keeping livestock in stalls, soil fertility increases by 53.76 °, assuming that these crop rotations occupied the field for 10 years, etc.
With the help of all these schemes, it was thus possible to evaluate the introduced system of field cultivation and crop rotation, to determine the amount of fertilizer needed, the methods of processing, the known sequence of plants, etc.
If the stated views of A. Thaer on soil fertility in general and on the processes of nutrition of cultivated plants in particular found, one might say, an enthusiastic reception among practical workers who got the opportunity to solve a number of complex economic issues through simple mathematical formulas, then, being built mainly on speculative premises and being deprived of the necessary experimental base, these views in themselves contributed little to the scientific development of plant nutrition issues, however, serving as a powerful impetus to a number of subsequent direct studies of this issue through appropriate experiments.
However, such an approach to resolving the question of the direct participation of organic substances in plant nutrition was made a long time ago, and there were separate attempts in this direction even before the appearance of the above-mentioned book by A. Thaer. Among the works of an experimental nature on this subject, we mention the research of Risler and Verdeil, who, using an aqueous extract from arable soil, found that organic substances can pass through the plant membrane and thus serve as a source of plant nutrition. Risler, in particular, pointed to the possibility of assimilation by higher plants from the organic matter of the soil and the carbon they need.
Saussure's longstanding experiments with growing plants in solutions of black humus substances also pointed to the possibility of their direct absorption by plants. Thus, after placing a leguminous plant in the above solution, Saussure stated after 14 days an increase in the weight of plants by 6 g - with a decrease in organic matter from a solution of 9 mg; in another experiment, Polygonum perscaria absorbed 43 mg of a humic substance from such a solution, increasing in weight by 3.5 g. In this case, the author observed a discoloration of the black solution from which the above plants drew their food. Plants with damaged roots of the solution did not discolor and humic substances were not extracted from it. Similar results were obtained by Soubeyran, Malaguti, Bouchardat and others.
It should be noted that Saussure, while admitting the possibility of the perception of humus substances in the soil by cultivated plants, at the same time, with a number of his remarkable works, contributed to a significant elucidation of the true role of plants and minerals in the life of plants, expressing a number of considerations and conclusions on this issue, which, one might say, adhere to. modern science.
Experiments made by some authors with the rapid discoloration of a rotting, foul-smelling liquid under the influence of growing roots grown in this liquid. various plants, were also interpreted as facts proving the possibility of the perception of organic compounds by higher plants. Corenwinder received in a mineral nutrient medium beetroot weighing 490 g and containing 60.07 g of sugar, while beetroot of the same variety, grown on soil consisting almost entirely of humus substances, weighed 1145 g and contained 121.27 g of sugar. Petermann in his experiments with soil dialysis showed that part of the organic matter of these soils passes through the parchment membrane freely and, moreover, in significant quantities. So, in the course of 10 days, out of 100 g of soil passed through the parchment membrane:

Вreal grew plants: a) in water with an addition of nitrates and potassium phosphate and b) in water with an addition of calcium perhumate. In the latter case, the plants produced significantly more dry matter in their aboveground and underground organs than in the former, when the plants fed only on mineral food. So,

In other experiments, Breal stated that a black solution of potassium and sodium humic acid quickly discolored in places where plant roots came into contact with them, which also indicates, in the author’s opinion, a certain effect of these roots on soil organic matter and the possibility of its perception by plant roots.
In the experiments of Deherain, some moth plants, using calcium perhumate, yielded a larger amount of dry matter in the crop than coeval specimens grown on a purely mineral substrate.
In another experiment, Deherain obtained beet on soil very rich in organic matter, 410 g in weight with 15.04% sugar, and on soil very poor in organic matter, but abundantly fertilized mineral fertilizers- in 92 g weight with 11.11% sugar. On the basis of these and other experiments of his own, and also comparing their results with the data of other authors, Deherain strongly inclines to the idea that higher plants can absorb humus compounds in the soil. In the experiments of Schulze, a young beet plant took up the solution of humus extract with such greed by its roots that already after 2 hours from the beginning of the experiment it was possible to ascertain a decrease in the nutrient solution of organic matter. Hoveler certifies that some higher plants are able to use not only amorphous humus compounds of the soil, but even freshly dead tissues that still retain their clearly distinguishable organization, as his morphological studies of pieces of dead wood pierced with roots convinced him. During these studies, it was stated that the cells of a dead tree are disorganized, turn black and form a black ring around the ingrown living root. This disorganization of the tissue progresses rapidly, the tissue becomes looser, the root sprouts and enhances the further use of organic matter. Boehm has shown that in etiolated leaves of leguminous plants, containing no trace of starch, starch synthesis can be induced in the absence of light if such leaves are placed in a glucose solution. Consequently, this carbohydrate, penetrating into the cells, one way or another is used there; similar conclusions are drawn by the mentioned author from his experiments on feeding buds separated from the mother plant with a sugar solution. Franck pointed out the possibility of the perception of soil organic compounds by some plants (mainly woody ones) with the help of symbiosis with mycorrhiza (Micorrhiza), which is very often observed just on soils rich in humus; later, cases of the same symbiosis were also indicated in some garden and agricultural plants (mainly in moths - O. Lemmermann and others).
Further references were made in the literature to instructive examples of alien plants that can feed on the organic substances of other plants, etc.
In parallel with the work aimed at proving the possibility of direct perception of soil organic compounds by higher plants, brewing in scientific literature the direction is diametrically opposite, trying to prove that the humus substances of the soil are completely inaccessible to plants and that the main and only source of plant nutrition is exclusively the mineral part of the soil. The most resolute and irreconcilable opponent of the humus theory of plant nutrition is J. Liebig (see below). It is all the more interesting to note Grandeau's original attempt to reconcile, as it were, these two extreme views by creating the so-called organo-mineral hypothesis of the nutrition of cultivated plants.
Having subjected to chemical analysis the chernozem soil from Uladovka and the soil from the vicinity of Luneville, Grandeau drew attention to the fact that the former is inferior to the latter in terms of the content of mineral substances (mainly phosphoric acid and potassium), as well as nitrogen, while in terms of productivity it significantly exceeds it. (Thus, Uladovo black soil without fertilizer gave the same yields as Luneville soil is able to give only with abundant fertilizer). This circumstance forced Grandeau to look for some other explanation for the high yields that are obtained on the black earth. Taking for experience a number of soils (Uladovsky chernozem - very high fertility, Luneville soil - medium fertility, sandy soil from under the pine forest - very little fertile, peaty unproductive soil in the vicinity of Nancy, etc.), Grandeau subjected to a detailed chemical study that "black substance", which, as we know from the previous presentation, passes from the soil into the ammonia extract after preliminary treatment of the latter weak hydrochloric acid, and found that the more fertile the soil, the more ash compounds are contained in the "black matter" of such soil. So, in 100 parts of the "black substance" found:

Studying, further, the phenomena of dialysis of the solutions of the “black substance” obtained by him, Grandeau observed an interesting phenomenon, namely: if it is not possible to open the mineral elements contained in this substance from the “black substance”, then in a solution that has passed through dialysis, it is quite possible precipitate with conventional reagents both phosphoric acid, and lime, and magnesia, etc. Based on the results obtained, Grandeau suggested that “the organic compounds of the“ black substance ”serve, as it were, for the movement of mineral substances and that, entering into a combination with the latter, they make them soluble in an environment in which, in addition to them, they are insoluble. "Diffusion destroys this compound - the plant membrane is permeable only to inorganic bodies, while for organic matter it serves as an insurmountable barrier." Grandeau summarizes his final judgment on the role of soil humus compounds in the processes of plant nutrition as follows; "... organic matter soils do not serve as nutrients for the plant, but ... they play the role of engines of mineral substances, the real nutritional principles of the plant organism. With such a judgment, Grandeau seems to reconcile the extreme views of A. Thaer and I. Liebig: "... mineral elements, remaining the necessary and only food for plants ... cannot become digestible ... without the mediation of organic substances"; the latter, not being assimilated by the roots, “transfer mineral elements into a soluble state; the formed organo-mineral compound is destroyed by the roots of plants, which take inorganic principles from it and leave organic ones aside.
In order to finally establish himself in his assumptions, Grandeau organized appropriate experiments on growing plants. In one vessel, plants were grown on unmodified soil (chernozem); in the other - on the same soil, but previously deprived of its "black substance" in the above way, and in the third - on calcined sand, to which the black extract from the previous treatment was mixed. The yield in the first and third vessels was much higher than in the second, where the plants developed very poorly, from which Grandeau concluded that the black organo-mineral substance is indeed the main source of nutrition for cultivated plants. Grandeau's views were also supported by some later French authors (Lefevre, Cailletet, and others).
Grandeau's work met with a number of objections (Pitsch, Tuxen, the late Kostychev, Eggertz, and others). It was pointed out, among other things, that the pre-treatment of the soil with hydrochloric acid (to displace humus acids from their salts), inevitably extracting some of the mineral compounds from it, is a factor that already reduces its fertility, that the direct use of ammonium carbonate is also accompanied by a partial dissolution of a certain amount of silicic acid. soil salts, as well as phosphate salts of lime and iron, etc., that the decantation of the "black substance" without its subsequent filtration through a clay filter is insufficient in view possible pollution its finest suspensions (Slezkin, Nefedov), which, finally, during the dialysis of organo-mineral substances, the easy elimination of ash compounds from them is explained by the processes of the decomposition of humus that has begun and its subsequent mineralization, etc.
At one time, the studies of those scientists who attributed direct participation in the nutrition of plants to soil humus and who were quoted by us above were subjected to very versatile criticism. So, best height plants in an environment rich in humus substances in comparison with the mineral substrate, tried to explain in other ways physical properties such an environment; the passage of soil organic compounds through the dialyzer was considered in no way to prove the physiological necessity for plants of these compounds passing through the dialyzer, etc.
The most vulnerable side of all the experiments described above is undoubtedly the fact that they were carried out under non-sterile conditions, and thus there was no certainty that the plants perceived organic substances as roots, and not the products of their decomposition and mineralization, as a result of the processes occurring in the subjects. organic compounds of biochemical transformations.
The end of the last century and the beginning of this century were marked by the appearance of a number of works, directly or indirectly trying to clarify the controversial issue of the possibility for higher plants feed directly on the organic compounds of the soil. Some of these works approached the solution of this problem by way of suitably organized experiments on the direct nutrition of plants with certain organic substances using very precise research methods, others tried to clarify this question indirectly, namely, by studying the nature and properties of plant root secretions, so that on the basis of This study will allow us to approach the question of what changes these secretions can produce in an organic substrate.
Thus, Molisch, confirming the old observations of Sachs that the roots of plants, acting in a restorative way, decolorize the liquid solutions of the chameleon, showed that the restorative secrets are secreted by the roots of plants outward into their environment. On the same substances as guaiac, pyrogallic acid and humus, plant secretions act in an oxidizing way. The ability to oxidize guaiac in root secretions appears to be in common with fresh plant sap. Pyrogallic acid (and tannin) are oxidized even more easily, which is why, in their presence, guaiac does not change with the assistance of the roots; This is explained by the fact that the entire oxidizing effect of the latter is used in this case by pyrogallic acid (and tannin), which is more easily oxidized, so that the oxidizing principle is lacking in guaiac. Solutions and precipitates of humic compounds acted similarly to these substances, namely, preventing an oxidizing effect on guaiac wood, they themselves were vigorously oxidized. Further, Molisch was the first to point out the conversion of cane sugar (in liquid solutions) by the roots of peas and beans into some reducing sugars, and this inverting action, as well as the above-mentioned oxidizing one, was explained by the release of the corresponding enzymes by the roots. Finally, we note the fact of the saccharifying effect of root secretions on starch paste, stated by Molisch. If we add to what has been said that the said scientist observed, in addition, the corrosive effect of the roots on a plate made of ivory (similar to the well-known experiments of Sachs with a marble plate), then one must come to the conclusion that the root secretions are able to chemically change organic substances and that the plant, therefore, can actively influence the humus compounds of the soil, modifying them in one way or another, for the purpose of further use as a nutrient. Molisch concludes his experiments with the words: “apparently, in the old, now completely forgotten humus theory of plant nutrition, there is still a grain of truth” ... We also see confirmation of the fact that oxidative enzymes are secreted by roots in the later works of Schreiner and Reed.
At the present time, we also have few studies that deal directly with the question of the use of this or that particular organic compound by higher plants. Stoclasa noted the high use of lecithin by oats as a source of phosphorus necessary for plants. The same was observed in their experiments with barley. Mitsuta, Aso and Jochida. Suzuki and Taeaichi observed a very significant use of phytin by barley. Egorov observed the same in his experiments with oats. Laurent, working with corn, peas, buckwheat and rye in solutions containing glucose in a CO2-free atmosphere, noted a significant increase in the dry matter weight of plants. Similar results were obtained by him in experiments with dextrin, starch, sugar, glycerin and potassium humate. V. Palladin, father, using a special method, also partly confirmed the possibility of assimilation of carbohydrates (sucrose) by higher plants.
In the longstanding experiments of Hatre, Jonhson, Wolff, and Knor, there are indications that higher plants can assimilate urea, uric and hippuric acid, leucine, tyrosine, glycocol, and others.
The possibility of nitrogen absorption by cultivated plants from urea and from uric acid was also stated by later studies by Thomson, who, in order to eliminate the possibility of feeding plants (oats, barley, peas and flax) with the decomposition products of the tested nitrogenous substances, placed the plants daily in fresh solutions (moreover, it was established by preliminary experiments that the products of this decomposition begin to appear no earlier than after 48 hours), etc.
In the work of Maze, we see one of the first attempts to cultivate plants on organic substrates under strictly sterile conditions, thus excluding the possibility of decomposition and subsequent mineralization of these substrates. Maze took solutions in which the following organic substances were introduced: sugar, starch, peptone, and humus substances isolated from the soil. All these substances were introduced into the vessels after the plants, having spent some time in normal solutions, had reached a certain development. Plants transferred to solutions of the mentioned organic substances continued to grow and develop normally, while those that were only in distilled water showed no weight gain. Plants that were in solutions with starch and humic substances had a particularly healthy appearance. "Higher plants," says Maze, "can grow, like chlorophyll-free organisms, at the expense of ready-made organic substances."
I. Shulov also conducted his experiments under conditions of meticulous sterility.
To resolve the question of whether higher plants can use phosphorus in organic compounds, the cited author took for his experiments compounds so widespread in plants and soils, such as lecithin and phytin. Working under sterile conditions, I. Shunov quite definitely proved the possibility of absorption and assimilation by plants (peas and corn) of phytin phosphorus (lecithin phosphorus turned out to be unaffected by plants in these experiments).
Studying the possibility of using organic nitrogen by higher plants, G. Petrov, also working under completely sterile conditions, showed that asparagine, for example, is freely absorbed by plants (corn) and "is a good source of nitrogen nutrition." The author suggests that the amide nitrogen of asparagine was consumed in this case: whether the more stable part of the asparagine nitrogen, namely the nitrogen of aspartic acid, was consumed remains unclear. The same author stated the possibility of assimilation by plants (corn) of the nitrogen of tyrosine, leucine and peptone. Somewhat later, I. Shulo proved that the plant (corn) absorbs not only the amide nitrogen of asparagine, but also absorbs and assimilates nitrogen and aspartic acid.
Let us further note the studies of Schreiner and Skinner, according to which nucleic acid, xanthine, etc. are capable of replacing soil nitrates as sources of nitrogenous food for plants. The chemical analysis of solutions carried out by the mentioned researchers during the growing season of the grown plants showed that no decomposition of the above organic compounds was observed, in view of which it was assumed that the named nitrogenous substances were directly perceived by the roots of the plants.
Finally, let us mention the studies of Hutchinson and Miller, who also worked under sterile conditions and ascertained the perception of nitrogen by pea sprouts from a humus solution isolated from garden soil: V. Byalosukn, who stated that higher plants (cabbage and white mustard) can perceive urea nitrogen, leucine, glycocol (in the presence of sugar), etc.
From the foregoing, it is clear that the question of humus substances in the soil as a direct source of nutrition for cultivated plants has not yet received a final resolution. At the same time, it should be noted that the possibility of perception and assimilation by higher plants of the organic compounds of the soil is increasingly being confirmed in the latest works.
For the knowledge of the physiological laws of plant nutrition, all the facts obtained in this area are, of course, of extremely great, one might even say, exceptional interest, but the importance of these facts from the point of view of their agronomic value should not be exaggerated. The fact is that if we admit, on the basis of recent work, that higher plants really have the ability to perceive and assimilate organic compounds, then it is unlikely that under natural conditions cultivated plants often have to use this ability: we must recognize the latter, nevertheless, so to speak, forced , and the higher plant resorts to it, apparently, only in cases of the complete absence of more digestible and more natural forms of nutrition for itself, i.e., in cases of the complete absence of mineral compounds in the soil, and we meet with such a case in natural conditions, of course, as with a rare and exceptional phenomenon, especially if we take into account that the organic compounds of the soil do not remain unchanged in this latter, but under the influence of various external factors are subjected, as we have seen above, to continuous processes of decomposition, decay and mineralization and, thus Thus, all the time they renew the reserves of mineral compounds in the soil.
If the obtained facts that establish the ability of higher plants to directly perceive and assimilate soil organic compounds are not yet of particular importance for agronomy (at least in the light in which these facts are drawn to us by the available works), then the significance of soil humus compounds as an indirect factor in life cultivated plant, a factor that determines a number of favorable properties soil environment, on the contrary, is, one might say, exceptional in its agricultural importance.

Topic: Organic substances of a plant cell, evidence of their presence in a plant.

Completed by: Timofeev Alexey Mikhailovich.

Group: 1-2KU

Teacher: Vinnik Valeria Konstantinovna.

1. Determination of organic substances.
organic substances - a class of compounds that include carbon (with the exception of carbides, carbonic acid, carbonates, carbon oxides and cyanides).
Organic substances (compounds) of the cell - chemical compounds, which include carbon atoms (proteins, carbohydrates, fats, nucleic acids, and other compounds that are not found in inanimate nature).
Different types of cells contain different amounts of organic compounds.
Plant cells - more carbohydrates.
Animal cells have more proteins.

2.History of appearance.
The name organic substances appeared at an early stage in the development of chemistry during the dominance of vitalistic views, which continued the tradition of Aristotle and Pliny the Elder about dividing the world into living and non-living. Substances were divided into mineral - belonging to the kingdom of minerals, and organic - belonging to the kingdoms of animals and plants. It was believed that the synthesis of organic substances requires a special "life force" inherent only in living things, and therefore the synthesis of organic substances from inorganic is impossible. This idea was refuted by Friedrich Wöhler in 1828 by synthesizing "organic" urea from the "mineral" ammonium cyanate, but the division of substances into organic and inorganic has been preserved in chemical terminology to this day.

3. Their classification.
The main classes of organic compounds of biological origin - proteins, lipids, carbohydrates, nucleic acids - contain, in addition to carbon, mainly hydrogen, nitrogen, oxygen, sulfur and phosphorus. That is why "classical" organic compounds contain primarily hydrogen, oxygen, nitrogen and sulfur - despite the fact that the elements that make up organic compounds, in addition to carbon, can be almost any element.
Squirrels
Amino acids are the structural components of proteins. Proteins, or proteins, are biological heteropolymers, the monomers of which are amino acids.
Lipids are fat-like organic compounds that are insoluble in water but readily soluble in non-polar solvents. Lipids belong to the simplest biological molecules.
Nucleic acids are phosphorus-containing biopolymers of living organisms that provide storage and transmission of hereditary information.
Carbohydrates
The very name "carbohydrates" reflects the fact that hydrogen and oxygen are present in the molecules of these substances in the same ratio as in the water molecule. In addition to carbon, hydrogen and oxygen, carbohydrate derivatives may contain other elements.

4. Structural analysis.
Structural analysis of organic substances.
Currently, there are several methods for characterizing organic compounds.
Crystallography (X-ray diffraction analysis) is the most accurate method, however, it requires the presence of a high-quality crystal of sufficient size to obtain high definition. Therefore, while this method is not used too often.
Elemental analysis is a destructive method used to quantify the content of elements in a molecule of a substance.
Infrared spectroscopy is used mainly to prove the presence (or absence) of certain functional groups.
Mass spectrometry is used to determine the molecular weights of substances and how they are fragmented.

5. Consideration in practice.
Organic compounds are present in almost all plants.
They differ significantly in the content of the main organic components: carbohydrates, fats, proteins.
The vegetative parts of plants - wood, straw, stems, leaves - contain a small amount of protein and fat and high level insoluble, difficult to decompose polysaccharides: cellulose, hemicellulose, as well as a polymer - lignin. The vegetative parts of plants are usually used as the basis of the substrate.
The generative parts of plants - fruits, seeds - contain a lot of protein and fat, a high level of readily available carbohydrates (starch, monosaccharides, disaccharides) and low level hard-to-reach polymers - cellulose, hemicellulose and lignin. Generative parts are used as nutritional protein-fat supplements.
All this plants receive with nutrition, which is divided into air and root.
With air nutrition, plants absorb carbon dioxide from the atmosphere to form organic matter during photosynthesis. The average content of carbon dioxide in the air is usually around 0.03%. In the surface layer it can be more. An increase in carbon dioxide in the surface layer of air is achieved by introducing into the soil organic fertilizers. Microorganisms in the soil digest these fertilizers and release carbon dioxide. Its increased content in the surface layer of air enhances photosynthesis and significantly increases the yield.
With root nutrition, plants absorb water and all the necessary elements of mineral nutrition from the soil with the help of the root system. From water, which is a source of hydrogen, as well as carbon dioxide from the air, plants create carbohydrates (sugar, starch and fiber), which account for up to 90% of all dry organic matter of plants. For the formation of proteins, plants also need nitrogen, sulfur, phosphorus. Big role potassium, calcium, boron, zinc, copper, molybdenum, iodine, cobalt, which are commonly called microelements, also play in the metabolism of plants. The lack of at least one of the nutrients in the soil will impair the growth and development of plants and lower their productivity.

Therefore, organic substances are present in plant cells and play an important role in development.

Sources of information.

1.http://ru.wikipedia.org.
2.http://www.chemistry.ssu.
3.http://www.krugosvet.ru

CHEMICAL COMPOSITION OF PLANTS
The chemical composition of plants- a complex of substances from mineral salts to high-molecular organic compounds in a plant organism. The vegetative organs and succulent fruits of most plants contain 80-95% water and only 5-20% dry matter. In seeds during ripening, the amount of water decreases, and the dry matter content rises to 85-90% of the total. weight. The dry matter consists of carbon (45%), oxygen (42%), hydrogen (6.5%) and nitrogen (1.5%). The rest (5%) falls on the so-called. ash elements (ash). Among them, there are: macroelements, the content of which is expressed in values ​​from tens of percent to hundredths of a percent; trace elements - from thousandths to hundred thousandths of a percent; ultramicroelements - millionths of a percent or less.

Macroelements, in addition to carbon, oxygen, hydrogen and nitrogen, include calcium, silicon, sodium, chlorine and iron; to trace elements - aluminum, barium, strontium, titanium, fluorine, rubidium, vanadium, chromium, bromine, germanium, nickel, lead, tin, arsenic, cobalt, iodine, lithium, molybdenum, yttrium and cesium; to ultramicroelements - selenium, cadmium, uranium, mercury, silver, gold, radium. The content of the same element in the tissues of one plant can vary under the influence of various conditions and depends mainly on its amount in the soil. For example, in various conditions culture, the content of phosphorus in plant tissues can range from 2.5 to 0.04%; boron from 0.01 to 0.001%, manganese - from 0.01 to 0.0001%, etc. Of the plant organs, leaves, tree bark and roots are rich in ash. Somewhat less ash in stems herbaceous plants, wood and seeds. Potato tubers, root, etc.. root crops are rich in potassium. All elements included in the plant organism, contained in it in the form of organic compounds, mineral salts, oxides, etc. They are localized in unequal quantities in certain places cytoplasm, cell organelles, tissues and organs of a plant. The most important substances of a living cell are proteins. In the green parts of the plant, in combination with protein, it contains - a substance with which it is carried out.

A special group of protein compounds that provide metabolism in the plant organism are enzymes. Nucleic acids (RNA and DNA) play a decisive role in intracellular metabolism, carrying genetic information and determining the type and structure of proteins in the cell. Their content in plants does not exceed 10% of the amount of protein.

Almost 90% of the dry mass of plants are carbohydrates, which are part of the cytoplasm of cells (sugar, starch, inulin), is the main. part of the cell wall (, hemicellulose), form intercellular plates (pectic substances). For the sake of carbohydrates, many crops are grown (for example, potatoes, in crop production, beets, cereals). An important high-energy group of organic compounds in plants are fats (oils) and lipoids.

Growth substances (, heteroauxin, kinetin) regulate the growth processes of a plant organism. Their quantitative content in plant tissues is very low (1 kg of germinating seeds contains about 0.5 mg of growth substances).

An important role in the metabolism of a plant organism is played by organic acids formed in the plant organism during the process of plant respiration and also by intermediate products of the synthesis of other compounds. Alkaloids occur in the form of salts of organic acids in plants. Other biologically active compounds quite common in plant organisms are glucosides. In special organs of plants are formed essential oils and resins, which are a mixture of a number of compounds, DOS. of which terpenes are unsaturated hydrocarbons.

Volatile biologically active substances of plant origin include and. All plants have phytoncidal properties to a certain extent. Along with compounds that take part in active metabolism, a number of polymers are synthesized in plants, which remain on the side of intensive metabolism (metabolism). These are fiber, rubber, gutta-percha, lignin (a substance that leads to the stiffening of plant cell membranes). Rubber can form approx. 2000 species of plants, but most of all in the tropics. tree - hevea, which contains gutta-percha. There is a lot of rubber in both coxagizi and tausagizi. Lignins various groups plants are slightly different. Especially a lot of lignin in wood (in conifers- up to 50%) and straw. During growth and chem. the composition of individual organs and plants as a whole changes to a certain extent (for example, nutrients accumulate in grain and fruits when they ripen, the content of cellulose and lignin in wood increases, and the relative amount of nutrients decreases with plant age, etc.). Organic compounds that are found in plant organisms originate from the primary products of photosynthesis and are the source of existence for the entire animal world.

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Topic: Organic substances of a plant cell, evidence of their presence in a plant.

Completed by: Timofeev Alexey Mikhailovich.

Group: 1-2KU

Teacher: Vinnik Valeria Konstantinovna.

1. Determination of organic substances.

2.History of appearance.

3. Their classification.

4. Structural analysis.

5. Consideration in practice.

6. Conclusion.

1. Definition of organic substances. Organic substances - a class of compounds that include carbon (with the exception of carbides, carbonic acid, carbonates, carbon oxides and cyanides). Cell organic substances (compounds) are chemical compounds that include carbon atoms ( proteins, carbohydrates, fats, nucleic acids, and other compounds that are not found in inanimate nature). Different types of cells contain different amounts of organic compounds. Plant cells - more carbohydrates. Animal cells - more proteins.

2. History of appearance. The name organic substances appeared at an early stage in the development of chemistry during the dominance of vitalistic views that continued the tradition of Aristotle and Pliny the Elder about dividing the world into living and non-living. Substances were divided into mineral - belonging to the kingdom of minerals, and organic - belonging to the kingdoms of animals and plants. It was believed that the synthesis of organic substances requires a special "life force" inherent only in living things, and therefore the synthesis of organic substances from inorganic is impossible. This idea was refuted by Friedrich Wöhler in 1828 by synthesizing "organic" urea from the "mineral" ammonium cyanate, but the division of substances into organic and inorganic has been preserved in chemical terminology to this day.

3. Their classification. The main classes of organic compounds of biological origin - proteins, lipids, carbohydrates, nucleic acids - contain, in addition to carbon, mainly hydrogen, nitrogen, oxygen, sulfur and phosphorus. That is why "classical" organic compounds contain primarily hydrogen, oxygen, nitrogen and sulfur - despite the fact that the elements that make up organic compounds, in addition to carbon, can be almost any element. Proteins Amino acids are the structural components of proteins. Proteins, or proteins, are biological heteropolymers whose monomers are amino acids. Lipids are fat-like organic compounds that are insoluble in water, but readily soluble in non-polar solvents. Lipids belong to the simplest biological molecules. Nucleic acids are phosphorus-containing biopolymers of living organisms that provide the storage and transmission of hereditary information. Carbohydrates The name "carbohydrates" itself reflects the fact that hydrogen and oxygen are present in the molecules of these substances in the same ratio as in the water molecule. In addition to carbon, hydrogen and oxygen, carbohydrate derivatives may contain other elements.

4. Structural analysis. Structural analysis of organic substances. Currently, there are several methods for the characterization of organic compounds. Crystallography (X-ray diffraction analysis) is the most accurate method, however, it requires a high-quality crystal of sufficient size to obtain high resolution. Therefore, while this method is not used too often. Elemental analysis is a destructive method used to quantify the content of elements in a molecule of a substance. Infrared spectroscopy is used mainly to prove the presence (or absence) of certain functional groups. Mass spectrometry is used to determine molecular masses of substances and ways of their fragmentation.

5. Consideration in practice. Organic compounds are present in almost all plants. They differ significantly in the content of the main organic components: carbohydrates, fats, proteins. The vegetative parts of plants - wood, straw, stems, leaves - contain a small amount of protein and fat and a high level insoluble, difficult to decompose polysaccharides: cellulose, hemicellulose, as well as a polymer - lignin. The vegetative parts of plants are usually used as the basis of the substrate. The generative parts of plants - fruits, seeds - contain a lot of protein and fat, a high level of readily available carbohydrates (starch, monosaccharides, disaccharides) and a low level of difficultly available polymers - cellulose, hemicellulose and lignin. The generative parts are used as nutritional protein-fat additives. All these plants are obtained with nutrition, which is divided into air and root. With air nutrition, plants absorb carbon dioxide from the atmosphere to form organic matter during photosynthesis. The average content of carbon dioxide in the air is usually around 0.03%. In the surface layer it can be more. An increase in carbon dioxide in the surface layer of air is achieved by applying organic fertilizers to the soil. Microorganisms in the soil digest these fertilizers and release carbon dioxide. Its increased content in the surface layer of air enhances photosynthesis and significantly increases the yield. With root nutrition, plants absorb water and all the necessary elements of mineral nutrition from the soil with the help of the root system. From water, which is a source of hydrogen, as well as carbon dioxide from the air, plants create carbohydrates (sugar, starch and fiber), which account for up to 90% of all dry organic matter of plants. For the formation of proteins, plants also need nitrogen, sulfur, phosphorus. An important role in the metabolism of plants is also played by potassium, calcium, boron, zinc, copper, molybdenum, iodine, cobalt, which are commonly called microelements. The lack of at least one of the nutrients in the soil will impair the growth and development of plants and lower their productivity.