RESPIRATION, PHOTOSYNTHESIS AND DROUGHT TOLERANCE IN MOSSES FROM VARIOUS HABITATS IN ISRAEL

Abstract

ABSTRACT The ability of six species of mosses, from three habitats in Israel, to resume photosynthesis and respiration after various periods of drying was examined. The relation between water content and the resumption of metabolic activity was studied. The desert mosses Tortula brevissima and Trichostomopsis aaronis resumed metabolic activity rapidly, even after prolonged drying, showed little damage due to high light intensities and did not require chlorophyll synthesis for resumption of photosynthetic activity. The Mediterranean moss Barbula fallax showed behaviour resembling that of the desert species while Homalothecium aureum was much more sensitive to drying and its recovery after desiccation was slower. Barbula tophacea, although collected from a moist habitat, resembled Homalothecium in many respects. Mniobryum sp. did not survive prolonged drying and showed almost no drought tolerance. Desert mosses clearly show very specialized adaptations to their habitat.