What Is the Impact of Soil Amendment With Biochar‐Filled Hydrogel on the Molecular Characteristics of Wheat ( <scp> <i>Triticum aestivum</i> </scp> ) Seedlings in Drought Stress Conditions?

ABSTRACT Elucidation of plant responses to innovative soil conditioners is necessary to introduce these agents into real crops as part of agrotechnical treatments of sustainable agriculture. In this study, the effect of a newly developed hybrid hydrogel synthesized based on alginate and filled with straw‐derived biochar on the molecular response of wheat plants in drought conditions was investigated. Quantitative molecular analysis of structural components, determination of protein molecular weight, SEM elemental mapping and immunolabelling for in situ observations were employed. The addition of the hydrogel significantly changed the adaptive behaviour of the plant. During drought, plant organs exhibited a less pronounced decrease in protein content relative to well‐watered controls. In plants grown without the hydrogel, a rapid increase in arabinoxylan and RG‐I content was observed, contrasting with the stable levels maintained in plants cultivated with the hydrogel. Anatomical analyses supported these observations—changes in leaves appeared after 20 days of drought in hydrogel‐treated plants, whereas such changes manifested as early as 5 days in plants grown without the hydrogel. Furthermore, roots from the drought‐stressed plants grown without the hydrogel exhibited the presence of a polysaccharide capsule layer, which was absent in roots from the hydrogel treatment. These findings suggest several hypotheses: hydrogel physically coats the root, thereby acting as a filter for soil solution solutes. The structural biology analyses presented here revealed for the first time that hydrogel influences the cell architecture.