Morphophysiological and antioxidant enzymatic mechanisms of seven Axonopus compressus variants grown under water stress conditions.

This study evaluated the morphological and physiological responses of a turfgrass species, namely the common Axonopus compressus and its six new variants to three soil water conditions, aiming to understand the performance and resilience of this turfgrass under climate-driven drought pressures. We conducted an 8-week glasshouse experiment with seven variants (A-0, A-1, A-40, A-46, A-91, A-122, and A-D) under three soil water conditions: W1 (100% field capacity (FC)), W2 (80% FC), and W3 (40% FC, drought stress). It was observed that under drought condition, there were reductions in leaf length, leaf width and turf height, while root mass increased and shoot biomass decreased. Under three soil water conditions, A-40, A-46, and A-122 exhibited finer-textured morphological traits compared to other variants. Although most variants showed a reduction in chlorophyll content under drought stress, A-46 showed an increasing trend, with total chlorophyll increased by 49.6% and carotenoids doubled compared to the most sensitive variant. Furthermore, the levels of proline, soluble sugar, and malondialdehyde (MDA) increased under drought conditions. A-40 exhibited 20.1% lower MDA content compared to the highest. Additionally, higher levels of soluble protein and antioxidant enzyme activities, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were observed in A-40, A-46, A-91, A-122, and A-D under drought stress. A-D exhibited 50.3% higher CAT activity, A-91 and A-122 showed about 30% higher POD activity respectively, compared to the most sensitive variant. This study demonstrates that A-40, A-46, A-122 and A-D possess improved morphological and physiological adaptations, showing enhanced tolerance to water stress in these new variants.