Physioanatomical adaptations in response to salt stress in Sporobolus arabicus (Poaceae) from the Salt Range, Pakistan

Sporobolus arabicus Boiss. is a perennial stoloniferous grass that prefers a saline or desert habitat. A natural population of Sporobolus arabicus growing in a salty area was compared with a normal nonsaline population. The salt-tolerant population showed better growth than its counterpart. Physioanatomical adaptations to saline environments in the salt-tolerant population were very specific. They included restricted toxic ion uptake, production of organic osmolytes, sclerification in roots, succulence in stem, and development of vesicular hairs on the leaves. These adaptations were not only for the excretion of toxic ions but also for the accumulation of inorganic ions in the parenchymatous tissue. The Salt Range population maintained osmotic and water potential, accumulated lower amounts of Na+. and Cl- in the roots and shoots, and had higher organic osmolytes, increased sclerification in the roots, and succulence in the stems and leaves.