We examined physiological mechanisms that enable different plant ecotypes of the same species to inhabit different ecological ecosystems, focusing on water availability. We tested the response of wild barley to water stress in desert and Mediterranean ecotypes, which were collected in different areas in Israel. We focused on different physiological parameters, regarding photochemical activity and nitrogen (N) assimilation in dehydrated leaves.

Results/Conclusions

Desert and Mediterranean ecotypes of barley showed a decrease in photochemical potential (Fv/Fm) which suggests that under low water contents in the leaves both species (and ecotypes) have decreased capacity for photosynthesis. In the Mediterranean ecotype of wild barley this decrease in photochemical potential was accompanied  by a significant increase in the non-photochemical quenching  of excess light, in the desert ecotype of wild barley there was only a slight increase in this parameter, this slower increase may allow the desert ecotype to preserve more of its photochemical capacity (as reflected in higher electron transport rate of photosystem II), allowing for example maintenance of higher N concentration in drying leaves.