Protein content in soybean seeds depending on the development of the symbiotic apparatus of plants under pre-sowing seed treatment with metabolically active substances

Abstract

Soybean is one of the leading legume crops in global agriculture due to the high content of plant protein and oil in its seeds. The growing demand for soybean products highlights the need to improve the biochemical composition of seeds through the use of effective plant growth regulators, which are an integral component of modern crop production technologies. Objective. To investigate the protein content in soybean seeds depending on the development of the symbiotic apparatus of plants following pre-sowing seed treatment with metabolically active substances. Materials and methods. Field experiments were conducted according to standard field trial methodologies. Protein content in plant material was determined using the Lowry method. Statistical analysis of the results was performed using mathematical statistics with the “Data Analysis” package in MS Excel 2016 and Student’s t-test. Results. The number and mass of nodules on soybean lateral roots increased until the end of the flowering stage, after which a decline was observed during the seed-filling stage, which can be explained by the redistribution of assimilates and carbohydrates in favor of reproductive organ formation. Pre-sowing seed treatment with a combination of vitamin E and ubiquinone-10 proved to be the most effective throughout the entire research period. During the flowering stage, the accumulation of nodule mass in the experimental treatments ranged from 185.23 to 289.87 mg per plant. The maximum total mass of nodules on lateral roots at this stage was recorded under pre-sowing seed treatment with the vitamin E + ubiquinone-10 combination. The use of this combination resulted in higher crude protein content compared with the variants where the growth regulator Vympel was applied. Conclusions. The number and mass of nodules on lateral roots increased until the end of the soybean flowering stage, whereas a decrease in both parameters was observed during the seed-filling stage. Among the tested compositions, the highest efficiency throughout the study period was provided by pre-sowing seed treatment with a combination of vitamin E and ubiquinone-10. A relationship between protein content in soybean seeds and the development of the plant symbiotic apparatus was established: higher crude protein levels were formed in plants with a greater number and mass of nodules on lateral roots. These indicators were most pronounced in plants grown from seeds treated with combinations of vitamin E + ubiquinone-10 and vitamin E + methionine + p-hydroxybenzoic acid + MgSO₄. The use of the vitamin E + ubiquinone-10 combination for pre-sowing seed treatment resulted in higher nodule number and mass on lateral roots and higher crude protein content in soybean seeds compared with the treatment using the growth regulator Vympel.