ارزیابی تحمل به شوری و خشکی در گیاه خیار با استفاده از برخی استرین‌های سودوموناس فلورسنت و باسیلوس سوبتیلیس

Water deficit and salinity are two limiting factors of plant productions in arid and semi-arid areas. Many adaptive strategies such as accumulation of osmotic adjustments, phenolic compounds and antioxidant enzymes activity have been developed in plants for dealing with drought and salinity stresses. Recently use of microorganisms, including PGPR bacteria, is one the management soil to improve the effect stresses. This experiment aimed to determine the effects of some bacterial strains on proline, sugar, total phenolic compounds (TPC), Phenylalanine ammonia lyase (PAL), photosynthesis pigments and antioxidant activities of cucumber plants under drought and salinity stress. Two completely randomized design were applied with a factorial arrangement of two factors: in the first experiment irrigation levels (70% field capacity (FC) as control and 30% FC) and bacteria strains (without inoculation as control, VUPF5, CHA0, T17-4, Bs96, BsVRU, BsVRU1) and in the second experiment salinity levels (0, 50 and 100 mM NaCl) and bacterial strains were done at three replications. The results showed that proline, sugar, TPC, PAL and enzymes activity in control and inoculated plants were increased by increasing drought and salinity stresses. By contrast photosynthesis pigments significantly decreased under stresses. Use of bacterial strains improved harmful effect of stresses by accumulation of proline, TPC, sugar, PAL activity and enzymes activity. The results also showed that inoculated plants had higher antioxidant activity compared to control plants under drought and salinity conditions. As a results use of PGPR is as suitable method to manage stress condition by increasing osmoregulator, TPC and antioxidant activity.