Morpho-physiological, biochemical, and leaf epidermal responses of Desmostachya bipinnata L. in arid habitats

The response of morpho-physiological and leaf surface attributes along with antioxidant potential of Desmostachya bipinnata L. populations collected from arid regions with 1.7–3.7 soil moisture % and =22.8–49.6 dS m−1 ECe was evaluated for adaptability to aridity. Among soil attributes, soil pH, ECe, moisture content, saturation percentage, organic matter, P, Na+, K+, Ca2+, Mg2+, Cl, NH4-N, NO3-N and plant attributes related to the morphology, physiology, antioxidant potential were studied. With increasing aridity root:shoot length ratio (0.1–0.4 cm) increased while average leaf area (12–4 cm2), shoot biomass (5–0.5 g), and root biomass (0.8–0.1g) decreased significantly. Parallel to that chlorophyll a (1–0.1 mgg−1 fresh weight) degradation was observed along with reduced carotenoid content (0.25–0.05 mgg−1 fresh weight). All other organic osmolytes decreased except for total soluble sugars which increased (0.10–0.15 μmol g−1 fresh weight) as the dryness ratio increased and more activities of the antioxidant enzymes APX (0.5–3.5 units mg pro−1), CAT (0.1–0.8 units mg pro−1), POD (0.02–0.25 units μg pro−1), and SOD (2–7 units mg pro−1) were observed. Among soluble cations, Na+ concentration increased (14–24 mg g−1 dw) in shoot as the aridity increased while shoot K+ (35–15 mgg−1 dw) and Mg2+ concentration decreased in both root and shoot tissues. Ca2+ concentration increased in root while N and P content decreased. In conclusion, aridity reduced overall vegetative growth but enhanced root growth for better absorption of water from the deeper layers with concurrent silica deposition in epidermal layers for controlling water loss.