The role and importance of carbohydrates in the vital activity of agricultural crops

Carbohydrates form the basis of the dry matter of plants, accounting for 80 to 90% of it. These organic compounds are formed during photosynthesis from carbon dioxide and water under the influence of solar energy. For an agronomist, carbohydrates are important as the main building material of the cell and the primary energy source for crop growth. The final harvest of dry matter, the sugar content of fruits, the starch content of tubers, and the strength of plant stems depend precisely on their accumulation.

• Content in dry plant matter — 80–90%
• Global photosynthesis volume — over 100 million tons/year
• Molecular weight of compounds — from 0.1 to 1 thousand kDa
• Daily human requirement — 500 g

In a plant organism, carbohydrates accumulate in seeds, tubers, roots, and fruits. This group of substances includes starch, cellulose, sugars, and pectin substances. In addition, they form cell walls and plant fibers. Carbohydrates serve as a basic energy source: during their oxidative transformation in cells, energy necessary for vital functions is released.

From a chemical point of view, these compounds combine hydroxyl and carbonyl groups, being aldehyde-alcohols and ketone-alcohols. The term itself was proposed in 1844, as hydrogen and oxygen are present in them in the same ratio as in water. The first studied compounds were described by the formula (CH2O)n where n ≥ 3. Later, exceptions were discovered: for example, deoxyhexoses (C6H12O5) or compounds with the addition of nitrogen, sulfur, and phosphorus. At the same time, acetic acid (CH3COOH) has a similar formula, but it is not classified as a carbohydrate.

Carbohydrate accumulation in crop harvests

The carbohydrate content in plants is not constant. It depends directly on the biological characteristics of the species, as well as on growing conditions — the level of mineral nutrition, water availability, and temperature regime. In the bodies of livestock animals and humans, the share of carbohydrates is only 2%, but they are vital for covering energy expenditures. Thus, when 500 g of carbohydrates are burned into carbon dioxide and water in the body, about 2,000 kcal of energy is released.