Water-retaining polymer in Dipteryx alata seedlings: strategy to mitigate the effect of water deficit

Water deficit is a stressful condition that negatively affects photosynthetic metabolism and plant growth. In an attempt to alleviate the effect of low water availability, the use of water-retaining polymer (hydrogel) has proven to be a viable strategy. We aimed to evaluate the effect of the hydrogel on photosynthetic metabolism and antioxidant protection in Dipteryx alata Vogel. seedlings under water deficit and on potential recovery in post-stress. The seedlings grown under the following water regimes: i) control - irrigated daily, ii) water deficit - suspension of irrigation, and iii) water deficit + hydrogel - addition of polymer in the time of transplanting. Assessments were carried out at photosynthesis close to zero and at recovery (resumption of irrigation after). We observed decreased in gas exchange and growth of seedlings subjected to water deficit in photosynthesis close to zero, but those with hydrogel maintained high values, in addition to a more efficient recovery. Although the hydrogel did not contribute to chlorophyll a fluorescence, it favored enzymatic regulation similar to control plants, especially peroxidase in leaves and roots, and superoxide dismutase in roots. D. alata responds to water deficit activating protective mechanisms through physiological and antioxidants adjustments that ensure its survival when exposed to water deficit and its recovery post-stress, indicating phenotypic plasticity. The hydrogel contributes positively to the photosynthetic, enzymatic, and quality maintenance of D. alata seedlings during and after stress.