effect of water stress on some physiological characteristics in three strawberry cultivars

to evaluate the effect of different levels of drought stress on some physiological parameters in strawberry, potted experiment involing strawberry cultivars  ‘marak٫ , ‘camarosa٫ and ‘gaviota٫ was conducted during summer 2009. the experiment consisted of three drought stress levels in three replications. the experimental arrangement was a factorial one, based upon a randomized complete block design. such physiological parameters as leaf relative water content (rwc), membrane stability index (msi), net photosynthesis (a), stomatal conductance (gs), transpiration (e) and chlorophyl content were assessed in leaves of strawberry subjected to different drought stress conditions. the recovery of these parameters was also studied after the plants started to be rewatered. it was shown that rwc, msi, a, gs, e, and chlorophyll content decreased with soil water content being reduced. ‘gaviota٫ cultivar bore a lower gs and transpiration rate than ‘marak٫ and ‘camarosa٫. recovery of these parameters occurred soon in all the cultivars. chlorophyll content in ‘gaviota٫ was higher than those in ‘marak٫ and ‘camarosa٫ under different treatments with chlorophyll recovery not taking place till one day past of the start of rewatering. level of prolin increased slowly in all the cultivars as drought stress increased. level of prolin in ‘gaviota٫ was higher than those of the other cultivars, but one day past of  rewatering, the level of prolin was sharply reduced.