Morpho-physiological responses of two differently adapted populations of cynodon dactylon (L.) pers. and Cenchrus ciliaris L. to salt stress

Two populations each of Cynodon dactylon (L.) Pers. and Cenchrus ciliaris L. collected from the Salt Range and Faisalabad were grown under control or saline (150 mM NaCl) conditions. Imposition of salt stress for 30 d decreased shoot and root biomass. However, salt induced reduction was less in the Salt Range populations of each grass species. Better adaptability of the Salt Range populations to salt stress was due to some heritable variation associated with their growth. Although photosynthetic rate along with stomatal conductance and sub-stomatal CO2 were higher in the salt-stressed plants of the Salt Range population of C. dactylon, there was no difference between both populations of C. ciliaris. Similarly, leaf proline was also higher in the Salt Range population of C. dactylon, while there was no difference between both populations of C. ciliaris for proline content. It is suggested that the Salt Range population of C. dactylon was better adapted to salt stress due to high accumulation of proline, which might have protected photosynthetic tissue from salt-induced damage because higher photosynthetic rate was recorded in plants with high proline accumulation. However, high salt tolerance of the Salt Range population of C. ciliaris might be due to factors other than those examined in the present study.