effect of drought stress on leaf water status, electrolyte leakage, photosynthesis parameters and chlorophyll fluorescence of two kochia ecotypes (kochia scoparia) irrigated with saline water

rainfall deficiency and the development of salinity in iran are the most important factors for using new salt and drought-resistant plants instead of conventional crops. kochia species have recently attracted the attention of researchers as a forage and fodder crop in marginal lands worldwide due to its drought and salt tolerant characteristics. this field experiment was performed at the salinity research station of ferdowsi university of mashhad, iran, in a split plot based on randomized complete block design with three replications in 2008. drought stress, including four levels (control, no irrigation in vegetative stage, no irrigation at reproductive stage and no irrigation at maturity stage for four weeks), and two kochia ecotypes (birjand and borujerd) were allocated as main and sub plots, respectively. relative water content, electrolyte leakage, photosynthesis parameters and chlorophyll fluorescence were assayed every two week from late vegetative stage. results showed that drought stress decreased significantly measured parameters in plants under stress, in all stages. plants completely recovered after eliminating stress and rewatering and recovered plants did not show significant difference with control. electrolyte leaking and chlorophyll fluorescence showed the lowest change among the measured parameters. it can emphasize that resistant to stress conditions in this plant and cell wall is not damaged at this level of stress situation. birjand ecotype from the arid region, revealed a better response than borujerd ecotype to drought stress. probably it returns to initial adaptation of birjand. in general this plant can recover after severe drought stress well. it is possible to introduce this plant as a new fodder in arid and saline conditions.