THE EFFECT OF WATER STRESS ON THE WATER REGIME PARAMETERS AND PHOTOSYNTHETIC PIGMENTS IN THE LEAVES OF SOYBEAN (Glycine max(L.) Merr) SAMPLES

The study was conducted on samples of soybean varieties Kyota, Krasnodar-68, Canada-3, Opus, Sinara. To assess the parameters of the water regime and the activity of photosynthetic pigments in plant leaves, intact plants were subjected to drought stress using a sucrose solution of 3.5 and 7.0 atm (8.7%) and salinization using a NaCl solution of 9 atm for 24 hours in laboratory conditions. The determination of hydration showed that there was no significant difference in this indicator for soybeans grown in natural field conditions (74.7-77.8%), but varietal samples of soybeans differed in water deficiency: the smallest water deficiency was recorded in varieties Kiota (12.8%) and Opus (13.6%), and the largest - in Canada -3 (23.8%). The relative water content was high in the Kiota variety, and the moisture retention capacity was higher in the Kiota and Krasnodar varieties - 68. Determination of the content of photosynthetic pigments in conditions of moderate and severe drought showed that, according to the sum of cl (a+b) pigments, the Kiota and Opus variants of the experiment were characterized by high indicators, and the Canada-3 and Sinara samples were low, chlorophyll degradation occurred under the influence of severe drought, with the exception of the Opus variant. Similar results were observed during salinization. In the experimental variants, in conditions of severe drought, a decrease in the content of carotenoids was observed. Visual observations did not reveal any signs of diseases of plants of the varieties Kiota and Opus. Experimental plants of Krasnodar-68 and Sinara varieties were infected with spotted rust (Septoria glycines Gemmy), Canada-3 plants with bacterial burn (Pseudomonas glycinea). Referring to the results of the study, it can be said that soybean plants demonstrate partial resistance to drought, as well as sensitivity to salinity. Compared with other experimental variants, Kyota and Opus samples can be considered resistant to drought and diseases.