Adaptations in Imperata cylindrica (L.) Raeusch. and Cenchrus ciliaris L. for altitude tolerance

Understanding how plants superpass high altitude and survive successfully in life-threatning abiotic condition is crucial for predicting their response to climate change. Plant strategies to beat cold are characterized by morphological and physiological adjustments. Here we studied the variations in leaf anatomy and physiology of two grasses Cenchrus ciliaris (Cc) and Imperata cylindrica (Ic) dominating in western Himalayan grasslands which are driven by elevation. We collected leaves of each grass from upper most canopy from three different elevations of district Poonch viz., lower site Paniola (1310 m a.s.l.), middle site Banjosa (1780 m a.s.l.) and higher site Tarkhul (2100 m a.s.l). Results showed that both grasses dodge the aggressive climatic forces by modifying anatomical setting and changing physiological adjustments. Elevation controls the conductive tissues by reducing vessel size and extensive sclerified tissues around the vascular bundles help the plant to avoid cavitation induced in cold conditions. The better physiological adjustment of these grasses at high elevation is ascribed to high proline and sugar present in leaves and accelerated activities of catalase (CAT) and peroxidase (POD) show scavenging ability of these grasses at high altitude. The low activity of malondialdehyde (MDA) is related with lower lipid peroxidation. These results bring novel information on how ecological factors influence the evolution of anatomical and physiological adaptations in high altitude plants.