بررسی مقایسه ای تاثیر تنش خشکی بر شاخص‌های فیزیولوژیکی و دفاعی برخی ارقام گیاه سورگوم در شرایط کشت درون شیشه‎ای

In natural environment and agricultural conditions, plants are frequently exposed to environmental stresses. One of the main factors reducing the worlds agricultural production is drought. In this research the effect of drought stress on physiological parameters of some cultivars of sorghum was studied in vitro. The seeds of sorghum were sterilized and then were cultured in MS medium supplemented with mannitol at percentages of 0, 2, 4, 6 and 8 (various levels of drought). Percentage of seed germination was measured seven days after planting. After 3 weeks, morphological and biochemical parameters were measured in treated plants. The results showed that increasing of drought stress in different varieties, the percentage of seed germination was reduced. Red sorghum on a percentage of germination was more susceptible than others. In all of the variety of sorghum, length of shoot and root, dry and fresh weight of shoot and root, content of chlorophyll and carotenoid were decreased. Content of Flavonoid, sugar, anthocyanin, proline , protein and activities of catalase, ascorbate proxidase and superoxide dismutase increased in shoot and root. The results showed that all of varieties of sorghum were resistant against of drought stress with typical changes in morphological and physiological parameters.