Adaptive Mechanisms of Halophytes in Desert Regions

Abstract

Plants growing in desert regions have to face a number of environmental adversaries such as high temperature, soil salinity and water stress due to low precipitation. Halophytes are among the successful plants that grow in desert saline regions. Halophytes use many different strategies to survive under these conditions. Some halophytes seeds can germinate in the presence of high salinity. Seeds of other halophytes are kept dormant due to the high salinity, but germinate when the rains come and reduce the salinity on the seeds. Persistent seed banks can be a source for new halophyte seedlings which permits seeds to germinate over different time periods when conditions are more favorable. Some root systems of halophytes can exclude salts. Other halophytes accumulate NaCl or synthesis osmotically compatible solutions such as proline, glycine betaine in their shoots to increase their ability to absorb water. Secreting salt from salt glands can reduce the salt level in certain halophytes. In other cases, the salt is compartmentalized in certain tissues of halophytes, which act as salt storage away from growing cells. Generally ion pumps prevent the salt from concentrated in cells that photosynthesize. Often halophytes develop succulence, which dilute the level of salt in the plant and stores water for use during dry periods.