The effect of epibrassinolide and its sulfuric acid esters on the morphometric parameters of sunflower Helianthus annuus L. (cv. Helios)

A step-by-step study of the biological activity of 24-epibrassinolide (EB) and its sodium salts of esters with sulfuric acid (sodium 2-, 3-, 22and 23-monosulfates and disodium 2.3-disulfate EB) was carried out in experiments on the effect on the growth parameters and crop yield of annual sunflower Helianthus annuus L. (Helios variety) depending on growing conditions. In experiments on a groundless medium, the effect of epibrassinolide sulfuric acid esters on primary plant growth at concentrations of 10–11–10–9 М turned out to be insignificant (with the exception of disodium 2.3–disulfate EB), to a greater extent the activity of the studied compounds was marked in laboratory experiment in soil culture. The greatest effect on growth and development plant was noted in field experiments. It is shown that the most effective and universal compound according to the studied parameters for two types of treatment (soaking seeds and spraying plants) is disodium 2.3-disulfate EB.