Reducing the effects of drought stress in fresh bean cultivation using super absorbent hydrogel

Under abiotic stress conditions, hydrogel polymers with the ability to retain water and nutrients have become a significant focus of research. Similarly, the addition of biochar is also known to support plant growth under such stress conditions. In this study, the effects of superabsorbent hydrogels (SAHs) composed of alginate-based hydrogels and biochar derived from plant peels, applied at different doses, on the cultivation of beans (Phaseolus vulgaris L.) under drought stress were investigated. Six different treatments were employed: control, drought, drought + 0.5 g SAH, drought + 1.5 g SAH, drought + 2.5 g SAH, and drought + 3.5 g SAH. Drought stress adversely affected the morphological and physiological characteristics of the plants. It also increased the concentration of reactive oxygen species (ROS), leading to lipid peroxidation, which caused damage to lipids and resulted in the formation of lipid radicals. This process led to an increase in malondialdehyde (MDA) levels, a critical biomarker of oxidative stress. However, it was determined that SAHs, applied at different doses, mitigated the adverse effects of drought on physiological parameters such as relative leaf water content, stomatal conductance, leaf water potential, and chlorophyll content. Notably, the application of 2.5 g SAH significantly reduced MDA levels. SAHs were found to strengthen the antioxidant defense system in plant tissues under drought stress, thereby reducing oxidative damage. This effect was associated with increases in phenolic and flavonoid components, as well as activities of proline, ascorbate peroxidase (APX), glutathione reductase (GR), and superoxide dismutase (SOD). Furthermore, SAHs alleviated the negative effects of drought on growth parameters, such as plant weight, root length, root weight, and leaf number. Keywords: Beans, Drought Stress, Superabsorbent Hydrogel, Biochar.