Glycine Betaine as a Reliable Strategy to Improve Drought Tolerance in Trachyspermum ammi

Abstract

Drought is a major abiotic stress that limits crop growth and productivity by inducing physiological and biochemical changes. Trachyspermum ammi L. is cultivated in arid and semi‐arid regions and is susceptible to drought stress. Osmoregulators like glycine betaine (GB) are known to enhance plant tolerance by regulating internal metabolic processes. This study aimed to evaluate the impact of GB foliar application on the physiological and morphological attributes of T. ammi under drought conditions. A pot experiment was conducted with three treatments: water spray (control), 5 mM GB, and 10 mM GB, whereas drought stress was maintained at 60% field capacity. Drought stress significantly decreased growth‐related attributes. Further, it has been noticed that the drought stress significantly increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in T. ammi . Application of GB at 10 mM significantly increased POD (41.2%) and CAT (312.3%) activities, whereas 5 mM GB led to the highest increase in ascorbate POD (100%) under drought stress. Foliar application of GB also mitigated the adverse effects, improving growth‐related attributes, photosynthetic pigments, and ions uptake and decreasing malondialdehyde (MDA) and H 2 O 2 . Among treatments, 10 mM GB exhibited greater efficiency under drought, whereas 5 mM GB was more beneficial under control conditions. Taken together, the findings suggest that GB could serve as a potential drought‐mitigating agent for T. ammi cultivation.