Mitigation of drought stress effects on application of γ Notulae Botanicae Horti Agrobotanici Cluj-Napoca Mitigation of drought stress effects on sweet potato plants by sweet potato plants by application of γ----Aminobutyric acid Aminobutyric acid

Abstract

The goal of the present study is to examine the role of γ-aminobutyric acid (GABA) at control, 0.5, and 1 mM L- in reducing the effects of drought stress and enhancing field performance on sweet potato (Ipomoea batatas (L.) Lam. var. batatas) under 2 irrigation regimes (50% and 70% exhaustion of available soil water). The results showed that, the relative water content (RWC) was decreased by 8%, nutrient uptake such as N, P, K and Ca by 39%, 23%, 9% and 11% respectively and yield (by 46%). However, osmolyte content (free amino acids FAA, soluble sugars, and proline), lipid peroxidation (MDA) and activity of peroxidase (28%) showed significant increases due to water stress. In sweet potato plants, application of GABA (particularly at 1 mM L 1 ) showed a partial normalization of drought effects. The 1 mM dose was further active than 0.5 mM L-1 in enhancing SPAD rate, dry matter, and carotene content. Furthermore, the 1 mM L-1 dose enhanced plant growth, water status, osmotic adjustment, antioxidant defence, and nutritional acquisition. The 1 mM dose was more effective than 0.5 mM L-1 in alleviating drought effects, leading to better yield and enhanced physiological reactions. In general, application of GABA seems to be a useful priming method for semiarid sweet potato plants in reducing the negative effects of drought stress. Significant reductions in plant growth and leaf relative water content and total soluble solids were caused by water stress in sweet potato plants. Exogenous foliar application of GABA at 1 mM L-1 enhanced osmotic adjustment, water plant status, and antioxidant defence systems, also improved nutrient uptake in sweet potato plants grown under drought stress.