Comparative Effects of a Synthetic hydrogel and a bio-hydrogel on Lettuce (Lactuca sativa) plants under Water Stress

Water stress keeps increasing considerably due to climate change. Alternative solutions, such as improving soil water retention, have become imperative in order to maintain crop productivity in arid and semi-arid areas. This study focused on the use of two types of hydrogel to improve soil properties and enhance plant tolerance to drought conditions. The first type is a synthetic, commercially available hydrogel based on sodium polyacrylate, while the second is a hydrogel produced in our laboratory from carboxymethylcellulose and sodium alginate (CMC/SA). The two hydrogels were characterized regarding their physicochemical properties, including swelling capacity and biodegradability, and their effect on lettuce plants subjected to water stress was evaluated.

The results showed that the SAP hydrogel has a high swelling capacity (228.5 g/g) compared to CMC/SA (28.1 g/g). As for biodegradability, it was low in the synthetic hydrogel (26.52%) compared to the CMC/SA hydrogel (51.01%). Furthermore, the physiological, biochemical, and morphological parameters of lettuce plants under water stress showed greater improvement following treatment with the CMC/SA hydrogel compared to SAP treatment. These improvements suggest that the bio-hydrogel not only supports better water retention but also enhances the plant’s resilience mechanisms.

These findings underscore that bio-hydrogels derived from CMC and SA offer an eco-friendly and efficient strategy to improve plant tolerance to drought stress without adverse environmental impacts. Thus, the use of natural polymer-based hydrogels could represent a sustainable alternative for agricultural practices in water-limited environments.