Punica granatum has a noticeable adaptation to drought stress. The levels of the green leaf volatile trans-2-hexenal increased in response to drought stress suggesting a possible role of this compound in drought stress response in pomegranate. Punica granatum (L.) is a highly valued fruit crop for its health-promoting effects and it is mainly cultivated in semi-arid areas. Thus, understanding the response mechanisms to drought stress is of great importance. In the present research, a metabolomics analysis was performed to evaluate the effects of drought stress on volatile organic compounds extracted from the leaves of pomegranate plants grown under water shortage conditions. The time course experiment (7 days of water deprivation and 24-h recovery) consisted of three treatments (control, drought stress, and rehydration of drought-stressed plants). Plant weights were recorded and control plants were irrigated daily at pot capacity to provide the lost water. Fraction of transpirable soil water has been evaluated as indicator of soil water availability in stressed plants. The levels of proline, hydrogen peroxide and lipid peroxidation as well as of the photosynthetic parameters such as photosynthesis rate (A), stomatal conductance (g s), photosynthetic efficiency of photosystem II, and photochemical quenching were monitored after the imposition of drought stress and recovery as markers of plant stress. Constitutive carbon volatile components were analyzed in the leaf of control and drought-stressed leaves using Head Space Solid Phase Micro Extraction sampling coupled with Gas Chromatography Mass Spectrometry. A total of 12 volatile compounds were found in pomegranate leaf profiles, mainly aldehydes, alcohols, and organic acids. Among them, the trans-2-hexenal showed a significant increase in water-stressed and recovered leaves respect to the well-watered ones. These data evidence a possible role of the oxylipin pathway in the response to water stress in pomegranate plants.

One of the most important breeding priorities is the assessment and improvement of the resistance of cultivated fruit crop genotypes to environmental stressors. Abiotic factors often do not allow realizing the productivity potential of fruit plants, which entails a decrease in the efficiency of their cultivation and financial losses for producers. In this regard, varieties with increased resistance to extreme environmental conditions are of great importance. Therefore, it is necessary to develop and use practical approaches to study and isolate genetic sources of high stress resistance for use in plant breeding and introduction. The aims of the studies were identifying the potential for resistance of grapevine genetic resources to abiotic stressors (through physiological diagnostics) and assessing new highly adaptive genotypes. We studied varieties and wild forms of grapevine differing in ecological and geographical origin to determine the main photosynthetic indicators (the total amount of chlorophyll, chlorophyll "a" / "b") in connection with their drought resistance. As a result of the study, grapevine varieties -(Ag Shany, Ag kishmishi, Tozlaiyjy, Girmizi kishmishi) and wild grapevine samples No.71, 17 No. 78, 25 No. 43, No. 74, 3 No.34 were identified as the most drought resistant. As a result of the study, relatively drought-resistant samples were identified, which are recommended for use in breeding work. Determination of the degree of plant resistance to extreme environmental factors will make it possible to assess the prospects of varieties of various fruit crops, including grapevine, for different soil and climatic zones of Azerbaijan.