ANALYSIS OF THE CONTENT OF BIOLOGICAL PIGMENTS IN LEAVES OF WOOD PLANTS UNDER STRESS

Abstract

Sciences, Volgograd, e-mail: VSem89@mail.ru In the Volgograd region, drought is one of the main environmental stresses for woody plants. In the field, an experimental study of drought resistance by the content of biological pigments was carried out. The study used a portable meter of flavonoids, anthocyanins and chlorophyll – DUALEX SCIENTIfIC +. The objects of research were the leaves of 10-year-old plant organisms of the bush Zizyphus jujuba (large-fruited – ’Ta-yan-tszao’, ’yujanin’); medium-fruited – ’friendship’, ’finik’; small-fruited forms – ’Sochinsky’, ’Temryuksky’) on chestnut soils (Volgograd region, collections of the federal Research Center for Agroecology of the Russian Academy of Sciences). years of research: 2018 (with a dry summer period) and 2019 (hydrologically more favorable). Using a portable instrument, differences in the pigment content were revealed depending on the influence of environmental stresses (summer droughts, light exposure within the crown, climatic factors of the place of growth). During the growing season, the highest content of biological pigments was noted in the leaf apparatus of large-fruited forms (chlorophyll: 23,22–29,48 mg/cm 2 ; flavonoids: 1,79–1,96 mg/cm 2 ; anthocyanins: 0,14–0,21 mg/cm 2 ). The leaves of small-fruited plants are characterized by a lower pigment content (chlorophyll: 13,99–24,80 mg/cm 2 ; flavonoids: 1,57–1,73 mg/cm 2 ; anthocyanins: 0,10–0,16 mg/cm 2 ). In the dry period, the chlorophyll content decreases; the content of flavonoids and anthocyanins increases, which determines the mechanisms of plant adaptation to stress factors of a lack of water. In response to arid conditions, light intensity and water scarcity, the leaves of small-fruited varieties accumulated and synthesized flavonoids and anthocyanins more intensively, which confirms the best adaptation of these varieties to adverse environmental conditions. A study of chlorophyll revealed differences in its content along the vertical profile of the crown – it increases from top to bottom within the crown. It was established that, within the crown, the content of anthocyanins and flavonoids is inversely related to the concentration of chlorophyll. In more drought-resistant plant organisms, Zizyphus jujuba (´Temryuksky, ,Sochinsky´) under water deficiency, cell systems are less damaged due to changes in the content of biological pigments. The accumulation of flavonoids and anthocyanins can be part of the stress signal caused by drought and affect the adaptive