Evaluation of Photosynthetic Pigment, Antioxidant and Non-Antioxidant Activity and some Morphological Traits Changes under Drought Stress in Castor Plant (Ricinus communis L.)

Extended Abstract                                    Introduction and Objective: Drought stress is a major environmental stress that effects on plants Therefore, it is necessary to know the mechanism that plant shows in encounter of stress.Materials and Methods: In order to evaluate the effect of drought stress on physiological and biochemical traits of castor plant, a factorial experiment was conducted in a completely randomized design with three replications in Sari Agricultural Sciences and Natural Resources University in 1397-8. The first factor was 22 castor ecotypes and the second factor was drought stress with 5 levels, full irrigation, four levels (irrigation was cuted at the primary of spike growth) (11, 22, 33, 44 days after Irrigation cut off). In this study, traits including superoxide dismutase (SOD), chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, phenol, flavonoids and protein content, as well as morphological traits such as plant height and leaf area index were measured. Results: The results showed that activity of superoxide dismutase (SOD), the amount of protein, phenol and flavonoids increased significantly with increasing the intensity of stress while the amount of photosynthetic pigments and carotenoids as well as plant height and leaf area index showed a significant decrease with increasing level of stress. According to the results of cluster analysis under drought stress, castor ecotypes were divided into three clusters. Differences between ecotypes in the resistant group compared to sensitive ecotypes under drought stress in superoxide dismutase (SOD), chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, phenol, flavonoids, protein content, plant height and index Leaf area were 83.41, 83.33, 85.57, 84.21, 82.08, 88.7, 86.44, 86.81, 78 and 80.9%, respectively. According to the results, ecotypes 2, 3, 5, 8 and 19 were introduced as resistant ecotypes for future breeding. Programs.Conclusion: In general, it seems that resistant ecotypes due to the severity of damage less in terms of growth indices and further increase in the activity of superoxide dismutase (SOD) and accumulation of proteins, phenols and flavonoids, more resistance in Showed against drought stress.