Leaf anatomical adaptations of Cenchrus ciliaris L. from the salt range, Pakistan against drought stress

Drought is one of the most serious environmental hazards that Pakistan is facing at present. It is even more severe to the agricultural crops and only for that single reason vast arid lands remain uncultivated each year. Precipitation ratio, in general, too very low in most of parts of Pakistan and there is a crying need to hunt suitable germplasm, both from cultivated crops and forages, but also from natural adaptive species. For this purpose the Salt Range can be of inimitable value, as native flora seems to be well adaptive to several biotic and abiotic stresses. Biodiversity of the Salt range is of specific importance because many endemic species are adapted to various environmental stresses. Ecotype of potential drought resistant grass Cenchrus ciliaris L. was collected from the drought-hit habitat of the Salt Range, Pakistan. Ecotype of this species was also collected from normally irrigated soils of Faisalabad for comparison. The plants were subjected to three moisture regimes, viz. 100% FC (control), 75 % FC and 50% FC. Cenchrus ciliaris from the Salt Range adapted better to moderate and high drought levels. Grass species from the Salt Range showed some specific adaptation against severe drought condition. Increased succulence (leaf thickness), cuticle deposition under adverse climates accompanied by thick epidermal layer was crucially important for maintaining leaf moisture and preventing water loss through leaf surface. Reduced metaxylem area under drought stress was responsible for efficient water transport during adverse climatic conditions. Prevention of water loss under drought stress by highly developed bulliform tissue and reduced stomatal size on adaxial leaf surface make this ecotype excellent selection for arid and semi-arid regions.