A pot experiment was conducted to assess the effect of different levels of water deficit on physiological and biochemical characteristics of three of grapevine cultivars. The factors included three commercial Iranian cultivars (‘Yaghooti’, ‘Askari’ and ‘Keshmeshi’) and three levels of water deficit (100, 60, 30% F.C.). Cultivars under study showed different physiological responses to water stress. It was shown that plant height, shoot and root dry weight, root length, shoot/root ratio, relative water content (RWC), leaf membrane stability index and chlorophyll content decreased with soil water content being reduced. Levels of proline, catalase, ascorbate peroxidases and guaiacol peroxidase activity increased in all the cultivars as water deficit stress levels increased. Of all the cultivars, ‘Yaghooti’ had the greatest RWC, chlorophyll content, catalase and ascorbate peroxidases activity and proline. This results suggest that Yaghooti is more resistant to water stress than the two other cultivars.

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