Investigating some morpho-physiological and biochemical traits of Acacia (Acacia salicina) treated with superabsorbent polymers under drought stress condition

Drought stress is the most important abiotic stress that affects the growth and development of plants. One of the strategies for soil moisture management and plant tolerance to drought stress is the use of organic materials compatible with the environment, including superabsorbent polymers. In order to investigate some morpho-physiological and biochemical characteristics of Acacia seedlings, this research was conducted with three types of superabsorbent polymers (A200, SNF and Barbary) at three concentrations (0, 1 and 2 g/kg) at three levels of drought stress (one week, two weeks and three weeks irrigation intervals). This experiment was factorial in randomized complete block design with three replications under field condition. The results showed that drought stress caused a significant decrease in fresh and dry weight of shoot, photosynthesis, transpiration, relative water content, chlorophyll and carotenoid content and significantly increased ion leakage, proline and total carbohydrates. The application of superabsorbent polymers increased the tolerance of Acacia to drought stress so that the use of 1 g/kg Barbary superabsorbent polymers in the first week had the highest shoot fresh weight (144 g) and the amount of chlorophyll (1.73 mg/g fw). in the first week, the use of 1 g/kg A200 superabsorbent polymer increased the rate of photosynthesis by 5.48% and the use of 2 g/kg A200 increased the rate of transpiration by 41.66% and the relative water content of leaves by 11.06% compared to control (0 gr/kg A200). Also, in the first week, the use of 2 g/kg SNF super absorbent increased the amount of carotenoids by 36.58% compared to 0 g/kg SNF. The use of 2 g/kg A200 in the third week reduced ion leakage by 22.50% compared to 0 g/kg A200 in the first week. The use of SNF superabsorbent at a concentration of 1 g/kg in the first week reduced the amount of proline by 22.08% compared to 0 gr/kg SNF. Therefore, the use of superabsorbent polymers especially Barbary increases the tolerance of Acasia to drought stress.