Evaluation of photosynthetic parameters at phenological stages of lentil cultivars (Lens culinaris Medik.) in response to water deficit stress

In order to evaluate of the photosynthetic traits of lentil cultivars under water deficit conditions an experiment was conducted as a factorial arrangement in a completely randomized design with three replications in pot cultivation with four cultivars including Gachsaran, Kimia, Ziba, Robat and four stress levels of 25, 50, 75 and 100% of field capacity. Results showed that in all three phenological stages increasing water stress levels (25 and 50% of field capacity) leads to a significant decrease in lentil cultivars in terms of chlorophyll content, CO2 interacellular, net-photosynthesis, Fv/Fm and transpiration rate. Under 75 and 100% of field capacity, Robat and Gachsaran cultivars in all phenological stages had the highest photosynthetic traits. Under conditions of 25 and 50% of field capacity, Robat cultivar in comparison with Kimia and Ziba had a significant increase in photosynthetic traits, especially in seedling and flowering stages but at podding stage, there was no significant difference between cultivars for most traits. In physiological traits, it was observed that Robat and Gachsaran cultivars in all water stress levels had a significant increase in the relative water content (RWC), membrane stabaility index (MSI), consenteration of Ca, K in root and leaf. Under all stress levels, Kimia cultivar had the lowest chlorophyll content, CO2 interacellular, net-photosynthesis, Fv/Fm, transpiration rate, RWC, MSI, consenteration of Ca, K in root and leaf but there was no significant difference with the Ziba cultivar. According to the physiological and photosynthesis characteristics of pot cultivation, the results of this study showed that Robat and Gachsaran cultivars compared with the Kimai and Ziba cultivars are more tolerant to water deficit condition.