About the work of Vinnytsia regional branch of the Ukrainian Society of Plant Physiologists

Abstract

The work and the main scientific results of the Vinnytsia branch of the USPP from the moment of its formation to the present time are analyzed. The main direction of research is exogenous regulation of plants source-sink relations in the systems «photosynthesis—growth», «depot of assimilates—growth» in the heterotrophic phase of plant development, and «macrosymbiont—microsymbiont» in symbiotic nitrogen fixation systems. Gibberellin and antigibberellin preparations (retardants) were used to create different tension of source-sink relations. It was found that under the influence of retardants, the decrease in the linear growth rate was accompanied by an increase in the cytokinins content with a decrease in the indoleacetic acid content in stems and leaves tissues of a wide range of plants. The free gibberellins activity was lower compared to control. At the same time, the content of these phytohormones antagonist, abscisic acid, increased. The retardants increased the stem branching, leaves number, weight and leaf surface area, optimized the leaves mesostructural organization, resulting in an increase in the photosynthetic net productivity. These changes lead to increased crop productivity. Under the conditions of artificial combination of external (light/dark) and hormonal factors (gibberellic acid and retardants) during seed germination, changes in the functioning of the source-sink system in the heterotrophic stage of plant development from seeds with different reserve substances types were studied. Gibberellin stimulated the starch breakdown in both light and dark, but under conditions of germination in the dark, the rate of reserve seed starch use was higher. Gibberellin also stimulated the seed reserve proteins hydrolysis, but the process began after intensive starch hydrolysis. Peculiarities of regulation of source-sink relations in the system «macro—microsymbiont» during the processes of symbiotic nitrogen fixation under the action of antigibberellin preparations — retardants are revealed. It was found that the typical reaction of soybean plants to the paclobutrazol application was a decrease in the free form gibberellins activity and an increase in the abscisic acid content, which led to changes in morphogenesis. Under the retardants action, the processes of formation of the symbiotic complex «soybean—Bradyrhizobium japonicum» intensify, nitrogenase activity increased, crop yield rised.