Ecotypic Morphological and Physio-Biochemical Responses of Two Differentially Adapted Forage Grasses, Cenchrus ciliaris L. and Cyperus arenarius Retz. to Drought Stress

Crop performance and yield are the results of genotypic expression as modulated by continuous interaction with the environment. Among the environmental aspects, drought and salinity are the most important factors, which limit the forages, including grasses, on a global basis. Grass species have the ability to grow under low water conditions and can produce high dry yield, proteins, and energy in areas exposed to drought stress. For this purpose, we conducted the present study to understand the response of forage grasses under drought stress from two different regions (Salt Range and Faisalabad) of Punjab, Pakistan. Two ecotypes of each grass species (Cenchrus ciliaris L. and Cyperus arenarius Retz.) were grown in pots at the botanical research area, Government College University Faisalabad, Pakistan. A group of plants were subjected to drought stress (60% field capacity) and controlled (100% field capacity) after three weeks of seed germination. The results from the present study depicted that the fresh and dry weights of root and shoot were decreased significantly under drought conditions. Moreover, C. ciliaris of the Salt Range area showed more resistance and higher growth production under drought stress. The chlorophyll (a and b) contents were also decreased significantly, while MDA, total soluble sugars, and proline levels were increased significantly under water-limited environments in the C. arenarius of Salt Range area. Enzymatic antioxidants (superoxidase dismutase (SOD) and peroxidase (POD)) and leaf Na+ were significantly raised in C. arenarius under drought stress collected from the Faisalabad region. Cenchrus ciliaris showed higher level of H2O2, total soluble proteins, glycinebetaine, catalase (CAT) and POD compared to C. arenarius. It also retained more leaf and root Ca2+, and root K+ under drought stress. It was concluded from the study that C. ciliaris is more resistant to drought in biomass production collected from the Salt Range area. The results suggested that C. ciliaris can be more widely used as a forage grass under water-scarce conditions as compared to C. arenarius.