بررسی اثر تنش خشکی بر رشد و ویژگیهای ریختی نهال سنجد (.Elaeagnus angustifolia L).

One of the most significant challenges in arid and semi-arid regions is the presence of abiotic environmental stresses, particularly drought stress, which affects the growth and development of plants. Elaeagnus angustifolia, as a species resistant to drought stress, is utilized for revegetation of barren areas, soil conservation, and creation of green spaces. An experiment was conducted in Semnan city to assess the impact of varying levels of drought stress on one-year-old elm seedlings using a completely randomized design. The experiment included four stress levels: control (100% available water), mild stress (75% available water), moderate stress (50% available water), and severe stress (25% available water). The results indicated that there was no significant difference between drought stress levels regarding the height and diameter of seedlings, while significant differences were observed in leaf number, vitality, root dry weight, and stem dry weight. The control group and mild stress conditions exhibited the highest number of leaves (25), freshness (>95%), root dry weight (>5 grams), and stem dry weight (>8 grams). As drought stress levels increased, there was a noticeable decrease in the number of leaves, survival rate, freshness, root dry weight, and stem dry weight. Regarding the vitality of seedlings, it was found that vitality remained at 100% in all drought stress levels except for severe stress, where vitality gradually decreased to zero after 7 months. Generally, the results demonstrated that the best outcome, which included acceptable growth and optimal water consumption, was attainable under mild stress conditions (75% available water). Indeed, this species demonstrated the ability to endure moderate drought stress conditions (50% available water) with a 100% survival rate. Additionally, there was no significant difference in terms of the stem dry weight (7.5 grams) compared to the control sample. This indicates that the elm species is resilient to water stress and can be effectively utilized for planting in green spaces within dry climate regions. [ABSTRACT FROM AUTHOR]