Physiological and molecular traits conferring salt tolerance in halophytic grasses

Aim : This study was conducted to identify the physiological and molecular traits underpinning salt stress adaptation in halophytic grasses Urochondra setulosa and Leptachloa fusca. Methodology : To assess the salt tolerance potential of Urochondra setutosa and Leptachloa fusca, the rooted cuttings and seeds were collected from Rann of Kutch, Bhuj, Gujarat and ICAR-CSSRI Regional Research Station, Lucknow, India, respectively using physiological, biochemical and molecular traits. Results : Salt stress decreased the biomass production in both the species to varying extents. Leaf chlorophyll declined marginally (5-12%) in Urochondra and moderately (similar to 28%) in Leptachloa under various salt treatments compared to controls. The values of psi(w) and psi(a), i.e., 3.98 MPa and 760.5 mmol kg(-1) were obtained under salinity stress of ECe similar to 50 dS m(-1) in Urochondra whereas the values of psi(w) and psi(a) were - 3.63 MPa and 556 mmol kg(-1) in Leptachloa. Osmoprotectant (praline, glycine betaine, total soluble sugar) and epi-cuticular wax content increased with increasing sodicity/salinity stresses in both grasss. The results showed that both halophytic grasses maintained lower Na+/K+ in their roots and which excludes the salt through the shoots portion. Expression of NHX1 gene increased with an increase of not only sodic, but also saline stress in both the grasses. Interpretation : The results demonstrate that Urochondra has a better adaption towards salinity and Leptochfoa towards sodicity stress.