Drought tolerance evaluation of Haloxylon aphyllum by studying root morphology under water stress

A major part of drought tolerance mechanisms of Haloxylon aphyllum depends on the depth and number of lateral roots by which the required water is absorbed from more soil volume. Therefore، this research was conducted to evaluate H. aphyllum root morphologic variation and its response to water stress. Progenies of four genotypes taken from a plant population of the species were used in the experiment. Seedlings were exposed to four levels of water stress. At the end of growing period، several root characteristics، such as hairy root density، root length، and root volume were recorded. Genotypes were significantly different for the studied characteristics. The characteristics were highly affected by the water stress treatments. The root characters also varied in responding to the water stress treatments. Root increment at all levels of water stress was also noticeable. In other words، facing water stress، the plant species increased its roots to reach more water. Effects of water deficit on root volume were also noticeable، in such a way that the first level of water stress showed the most recorded root volume. This implies، facing water deficit، Haloxylon roots are increased to cover more soil volume to intake more water.