INTERSPECIFIC VARIATION IN PHYSIOLOGICAL AND METABOLIC RESPONSES OF 5SPECIES OF CYMBOPOGON TO WATER-STRESS

The effect of drought on physiological and biochemical responses viz. psi, RWC, plasma membrane damage, accumulation of proline, induction o f PEP carboxylase activity and essential oil biosynthesis in five spec ies of Cymbopogon (family poaceae) was investigated. The species diffe red considerably in their response to water deficit. A dramatic increa se in PEP carboxylase activity was observed in all of the cases; howev er, oil biosynthesis under drought increased in C. martinii and C. pen dulus while it decreased substantially in C flexuosus. Its level remai ned almost the same in C nardus and C winterianus. The effect of droug ht appears to be species specific. The physiological significance of P EP carboxylase induction and the effect of stress on oil biogenetic ca pacity are discussed.