Introduction World food security is being significantly hampered due to water scarcity (Mitter et al., 2015). Water stress is different from other stresses because unlike other natural disasters its effects remain even after its period terminates (Ashraf et al., 2010; Strauss et al., 2013). Soil water deficiency affects three major mechanisms in plants: reduced canopy absorption of photosynthetically available radiation (PAR), radiation use efficiency, and harvest index, and all of these lead to reduced plant yield (Fiala et al., 2014). Seedling growth and productivity are also severely affected, mainly due to low supply of water (Atkinson and Urwin, 2012). Due to drought stress, germination potential (Wang et al., 2011), hypocotyl length, and plant biomass are commonly hampered (Wang et al., 2015). During the initial stage of growth and germination, relative water content was high in wheat, which decreased as dry matter accumulated and leaf matured (Hajheidari et al., 2007; Kaur et al., 2007). Nutrient uptake and tissue level concentrations along with water relations are perturbed under water-limited conditions in crop plants (Losak et al., 2010). Drought stress causes the production of reactive oxygen species (ROS), which affect the ultrastructure of cell membranes and DNA as well as the functioning of cellular processes (Turkan, 2011; Sun et al., 2013; Kaya et al., 2015). ROS including hydroxyl radical, anion radical, hydrogen peroxide, alkyl radicals, and singlet oxygen are injurious to plant metabolic activities. These species may react to lipids, proteins, and DNA, which causes oxidative damage and abnormal functions of cells (Sarvajeet and Tuteja, 2010; Shafiq et al., 2015). It is known that absorption of thiamin by plant root, leaves, and

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.

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