GROWTH-STIMULATING ACTIVITY OF NEW BIOCOORDINATION HETEROMETALLIC BIS(CITRATO)GERMANATES (IV) OF WINTER WHEAT

The results of using synthesized and characterized heterometallic chelates using a combination of modern physicochemical methods for studying them are presented for the first time of bis(citrato)germanates(IV): [M(H2O)6][Ge(HCit)2]×nН2О, where M=Mn, n=4 (1); Fe, n=4 (2); Cu, n=1 (3); Zn, n=3 (4) (HCit3- is anion of citric acid) for pre-sowing treatment of winter wheat seeds in field conditions are presented for the first time. It was found that their addition to the mixture with the fungicide increases plants' germination and growth rates at the initial stage of autumn development when wheat especially needs the microelements necessary for biofortification and further crop formation. An increase in yield was recorded compared to the control, which is evidence of the creation of favourable conditions under which the studied bis(citratо)germanates (1-4) are well absorbed as chelate microfertilizers. They contribute to the disclosure of the genetic potential of winter wheat, effectively affect its growth and development, and increase the yield and quality of grain. At certain stages of winter wheat growth, the degree of manifestation of the growth-stimulating activity of compounds (1-4) varies depending on the composition of the complex cation. In the variant of application of [Fe(H2O)6][Ge(HCit)2]×4Н2О (2), field seed germination increased by 10.7%, an increase in the above-ground mass of plants up to 18 cm and the development of the primary root system up to 8.0 cm were recorded. The increase in yield also significantly depended on the variant of seed treatment. The best indicator was characterized by [Cu(H2O)6][Ge(HCit)2]×Н2О (3), which subsequently significantly influenced the formation of winter wheat grain and increased yield by 19.32%. It has been shown that the chemical design of such heterometallic compounds, built from bioactive, non-toxic complex cations and anions, which do not compete with each other for binding to the plant biosystem and jointly contribute to the overall growth-stimulating effect, opens up prospects for the creation of effective new generation drugs that are capable of providing a significant increase in the yield of grain crops