The effect of drought stress on some morphological and physiological characters in canola seedling (Brassica napus)

In order to study some morphological and physiological traits of susceptible (Hayola308) and tolerant (SLM046) genotypes of canola to drought stress, an experiment was conducted in CRD design with factorial split in time arrangement. The applied factors were genotype (susceptible and tolerant) and irrigation condition (non-stress and stress). The stress was applied at before flowering time and the traits were measured at 24, 48, 72 and 96 hours after it in both condition. The result showed a reduction in dry weight of root in Hayola308 genotype, and a significant increase in root to shoot length ratio, fresh weight of root and malondialdehyde level (MDA) in SLM046 genotype. The 48 hours after drought stress, the fresh weight of shoot in SLM046 genotype was higher than Hayola308 genotype. Relative water content (RWC) in SLM046 and Hayola308 at 24 hours after stress were 88.59% and 38.52%, respectively. In Hayola308 genotype, hydrogen peroxide (H2O2) content in stress condition was higher than non-stress ones. There was not a significant difference among studied treatments for electrolyte leakage. In general, the increase of root length, root to shoot length ratio, RWC, fresh weight of root and the difference between fresh and dry weight of root and shoot and no change in dry weight of root and H2O2 content in SLM046 genotype indicated that this genotype had traits which could assign tolerance to drought stress.