Salinity and Drought Tolerance of Atriplex halimus: Ecology of Xero-halophytes of Egypt

The book will focus on the abiotic stress, such as salt and drought, these are great danger that threats our crops productivity. Atriplex. halimus is a saltbush that naturally grows in saline environment on the Mediterranean coast; moreover, it is characterized by an efficient tolerance not only to salt but also to drought. The present study focused on evaluating the tolerance mechanisms of this plant under different levels of salt and drought stress. A. halimus had a unique nature, where its ability to grow in different habitats with different ranges of saline concentrations, moreover, A. halimus was detected with different species some of them were halophytes and others were xerophytes. The germination of A. halimus decreased with increasing the external concentration of NaCl and 500 mM NaCl completely inhibited the germination. The optimal growth of A. halimus in the vegetative stage was in the range between 50-200 mM NaCl and that was attributed to the increase in the photosynthetic rate and/or the increased protein level of PEPC. Salt and drought stress changed the metabolite profile of A. halimus.