Enhancing Growth and Biochemical Traits of Helianthus annuus L. Under Drought Stress Using a Super Absorbent Dextrin–Polyacrylamide Hydrogel as a Soil Conditioner

Drought stress significantly affects plant growth and productivity, including sunflowers (Helianthus annuus L.). Superabsorbent hydrogels, specifically composed of dextrin and polyacrylamide, offer a potential solution to mitigate drought stress and enhance the biochemical traits of sunflowers. This study explored the impact of copolymer composition on the gel fraction, swelling behavior, water retention, morphology, and chemical structure of dextrin (Dix)/polyacrylamide (PAAm) hydrogels synthesized via radical polymerization. Results revealed that the 50/50 ratio of the Dix/PAAm hydrogel exhibited desirable characteristics, including a heterogeneous pore structure (approximately 100 μm) and higher water absorption capacity attributed to a greater Dix content. In a pot experiment, the (Dix/PAAm) hydrogel played a crucial role in alleviating the harmful effects of drought stress on the growth, chlorophyll content, fresh shoot weight, and pigments in sunflowers. The hydrogel application positively influenced these parameters by enhancing water retention, nutrient availability, and physiological responses to drought stress. Overall, these findings highlight the potential of the (Dix/PAAm) hydrogel as an effective tool for enhancing plant resilience to drought stress and promoting growth and biochemical traits in sunflowers.