Morpho-physiological and biochemical responses of Vitex negundo to seawater induced salt stress

Salinity poses a significant threat to modern agriculture because it stunts and impedes crop growth and development. This experiment was aimed at examining the morpho-physiological, biochemical, and adaptive responses of Vitex negundo (Chaste tree) to a gradient of seawater (4 dS m-1, 8 dS m-1, and 12 dS m-1) for different durations (90, 120, and 150 days). The results demonstrate that seawater had a detrimental effect on morphological parameters as plant height, number of leaves, number of branches, and dry matter in a time and dose -dependent approach. This negative impact was strongly connected with the considerable reduction of many physiological indices such as relative water content, water retention capacity, photosynthetic pigments and carbohydrates content. Conversely, higher concentrations of proline indicated that Vitex negundo had improved osmoprotective abilities to combat salinity-induced osmotic stress. Increased H2O2 levels along with noticeably unaffected membrane fluidity suggest its function in detecting and adapting to stress at moderate salinity. Additionally, elevated antioxidant enzyme activity (SOD, CAT, and APX), DPPH, and ABTS', along with elevated phenol and flavonoid levels, point to a coordinated role for antioxidant elements that are controlling ROS. In contrast, high salinity (12 dS m-1) resulted in an explosion of ROS, as seen by elevated levels of H2O2, MDA, and electrolyte leakage. In the ion analysis, salinity-exposed plants revealed that the majority of Na' persisted in the roots, while K', Ca2', and Mg2' were more heavily accumulated in the leaves than the roots that assist in the uptake of other significant minerals. These results imply that Vitex negundo has the ability to withstand moderate (8 dS m-1) salinity due to its enhanced antioxidant system, osmolytes which also activates protective enzymes and improves ionic homeostasis. (c) 2024 SAAB. Published by Elsevier B.V. All rights reserved.