Genus -specific physiological and biochemical adaptations of turfgrasses to drought stress and exogenous calcium

Drought stress is one of the most significant challenges to the sustainability of grasslands in the era of climate change. Given the increasing scarcity of freshwater resources worldwide and the severe impacts of water deficit stress on plant performance, extensive global research efforts are underway to combat this stress and identify plant drought response mechanisms, aiming to enhance plant drought tolerance. This study aimed to investigate the effect of different calcium levels on the physiological and biochemical responses of four common turfgrass genera used in urban green spaces (Agropyron, Festuca, Cynodon, and Lolium) under drought stress. Plants were treated in two groups, control (well-watered) and under drought stress, with four different calcium concentrations (۰, ۵, ۱۰, and ۲۰ mM) in a completely randomized design. Growth, physiological, and biochemical parameters, including root and shoot longitudinal growth, relative water content, leaf ion leakage, changes in membrane lipid peroxidation, photosynthetic pigment content, proline content, and the activity of some antioxidant enzymes, were measured and analyzed. The results indicated that drought stress reduced shoot growth in all genera but led to increased root growth in Festuca and Agropyron. Calcium application had no significant effect on shoot growth but significantly increased the root growth of Agropyron under drought stress compared to the other genera. In the sensitive genera (Cynodon and Lolium), calcium caused a significant improvement in leaf width, relative water content, chlorophyll a content, and a reduction in ion leakage and membrane lipid peroxidation. In contrast, the resistant genera (Agropyron and Festuca) showed less response to calcium and primarily relied on intrinsic mechanisms such as high activity of SOD and APX enzymes. Based on the results, it can be concluded that the response to calcium is genus-dependent. Sensitive genera utilize calcium as an external modulator to enhance their defense system, whereas resistant genera, due to possessing more efficient intrinsic defense mechanisms, are less dependent on external calcium. The findings demonstrate that calcium application can be used as a management strategy, particularly in more sensitive turfgrass genus, to improve drought resistance.

کلیدواژه ها:

Ascorbate peroxidase ، Catalase ، Chlorophyll ، Ion leakage ، Turfgrass ، Ascorbate peroxidase ، Catalase ، Chlorophyll ، Ion leakage ، Turfgrass