Salt Tolerance in <i> Machilus faberi </i> : Elucidating Growth and Physiological Adaptations to Saline Environments

Abstract

'Qihong Yang' 'Xiaoying Yu' 'Lihong Yan' 'Yanlin Li'] Simple Summary In this study, the physiological response mechanism of Machilus faberi Hemsl under salt stress was discussed. In different salt concentration environments, we observed the growth status of and internal changes in plants. For example, plants of this species could still grow normally at a concentration of 100-300 mmol−1/L. These findings provide important theoretical data for the promotion of this species in saline-alkaline areas. This study provides a practical basis for the promotion of this species and fills the research gap of this species under abiotic stress. Abstract Adversity stress is the main environmental factor limiting plant growth and development, including salt and other stress factors. This study delves into the adaptability and salt tolerance mechanisms of Machilus faberi Hemsl, a species with potential for cultivation in salinized areas. We subjected the plants to various salt concentrations to observe their growth responses and to assess key physiological and biochemical indicators. The results revealed that under high salt concentrations (500 and 700 mmol−1/L), symptoms such as leaf yellowing, wilting, and eventual death were observed. Notably, plant height and shoot growth ceased on the 14th day of exposure. Chlorophyll content (a, b, total a + b, and the a/b ratio) initially increased but subsequently decreased under varying levels of salt stress. Similarly, the net photosynthetic rate, stomatal conductance, leaf water content, and root activity significantly declined under these conditions. Moreover, we observed an increase in malondialdehyde levels and relative conductivity, indicative of cellular damage and stress. The activity of superoxide dismutase and ascorbate peroxidase initially increased and then diminished with prolonged stress, whereas peroxidase activity consistently increased. Levels of proline and soluble protein exhibited an upward trend, contrasting with the fluctuating pattern of soluble sugars, which decreased initially but increased subsequently. In conclusion, M.