Microelements as a bioregulator

Microelements are activators and active components of many biochemical processes in plants, animals, and humans. They also participate in oxidation–reduction processes, exerting a direct or indirect influence on photosynthesis, respiration, and the biosynthesis of carbohydrates, proteins, pigments, vitamins, phytohormones, and others. They affect fertilization and the development of the ovum and embryo, the formation of meristem tissue, and the development of reproductive organs. They help increase plants’ resistance to low and high temperatures, drought, and fungal and bacterial diseases.

It has been established that the active participation of microelements in the metabolic processes of living organisms is largely determined by their physicochemical properties. Microelements have a tendency to form complexes with various organic compounds. Most often, these elements are found in plant cells in the form of various complexes with chelating agents such as EDTA, EDDHA, and DTPA. When bound to enzymes, they increase their catalytic function and enzymatic properties. About 30% of all enzymes known so far contain microelements in their molecules. Depending on the nature of the reactions, the functions of microelements vary, but they also share common features such as transporting electrons in the oxidative chain. Thus, cycles of biochemical reactions associated with photosynthesis, respiration, nitrate reduction, and molecular nitrogen fixation are carried out with the help of copper, molybdenum, manganese, and iron. Some microelements help form a specific spatial conformation of the protein molecule. In other cases, microelement ions can serve as a bridge between the enzyme and the substrate. For example, manganese, zinc, molybdenum, and copper have a similar effect on the photosynthetic activity of plants, while copper, boron, and zinc influence the movement of assimilates from the leaves to the generative organs and the roots. This similar and related action of microelements becomes especially evident at elevated ambient temperatures, which mainly inhibit the migration of assimilates.

It has been found that boron, manganese, zinc, copper, and cobalt, when combined with certain amino acids, increase the drought resistance of plants by enhancing the hydrophilicity and water-retention capacity of colloids. Due to the similar effect of microelements on metabolism, a positive additive effect is rarely obtained when simultaneously treating with several products containing microelements. Regarding yield increase, the effect is most pronounced when combining preparations containing microelements with protein hydrolysates, natural phytohormones, and humic acids.

Based on the above, it can be concluded that by increasing the concentration of microelements in plant tissues, certain enzymes can be selectively activated or inhibited, and specific physiological–biochemical processes related to germination, growth, development, and productivity of plants can be directed.