Patterns of ion excretion and survival in two stoloniferous arid zone grasses.

Desert plants show specific mechanisms to thrive under prevailing harsh conditions. To study the survival mechanism(s) in native desert plant species, Lesser Cholistan desert in Pakistan was surveyed and two potential salt secretory grass species, Aeluropus lagopoides and Ochthochloa compressa, were selected from five saline sites. Both these grasses responded differentially to saline environments by showing specialized mechanisms of survival including excretion of toxic ions through trichomes, vesicular and glandular hairs through leaf surface. In A. lagopoides, salt tolerance was associated with excreted Na(+) concentration through leaf surface and accumulation of useful ions like Ca(2+) and K(+) in the shoot. Contrarily, O. compressa excreted all the ions through leaves without discriminating among toxic or beneficial ions. Results suggested that A. lagopoides was more successfully adapted to saline desert environments than O. compressa by excretion of excessive toxic ions and retention of Ca(2+) and K(+) in the shoot. This appears to be an adaptive character of the former species to successfully thrive in harsh desert conditions.