Effect of Drought Stress on Some Growth Parameters and Several Biochemical Aspects in Two Pumpkin Species

For considering the effect of drought stress on some morphological and biochemical changes in two pumpkin species, Cucurbita maxima L. and Cucurbita pepo L. a kind of experiment was done by field culture in three water dispersal levels with field capacity, 2/3 field capacity, and 1/3 field capacity, based on the factorial design in random block form with four replications. The results indicated that increasing the stress level, leaves water potential under drought stress decreased in comparison to the control sample in both species. But with increasing drought stress, root length increased too. Also during drought stress, root soluble carbohydrates content, ascorbic acid content, dehydroascorbic acid, catalase, polyphenol oxidase, and peroxidase enzymes activity increased significantly in 5% level, according to the results with increasing the stress, soluble carbohydrates content decreased in leaf.