ORIGINAL ABSTRACT

The pursuit of sustainable alternatives has spurred interest in plant-derived bioherbicides with multi-target actions to combat resistance. This study explored the herbicidal potential of Agave lechuguilla extract (AGE) against the widely problematic weed Chenopodium album L. (lambsquarters). Various methods, including germination assays, biochemical profiling, measurements of antioxidant enzyme activity, isothermal microcalorimetry, and both macroscopic and microscopic morphological analyses, were employed to evaluate the effects of AGE relative to glyphosate (1.5%). The results indicated that AGE inhibited seed germination in a concentration-dependent manner, with the 30 g/L dose exhibiting the most significant effect. Treatment with 30 g/L of AGE led to a notable decrease in total carbohydrate content and catalase activity, an increase in total lipids, and an enhancement of glutathione reductase activity. Additionally, it suppressed metabolic heat output and severely disrupted root and cellular architecture, resulting in a reduction of cell area by 51.1%. In contrast, glyphosate primarily increased lipid content and induced near-complete metabolic suppression while causing distinct morphological and enzymatic alterations. The findings demonstrate that AGE functions as a multi-target pre-emergence bioherbicide, disrupting processes related to germination, metabolism, oxidative balance, and morphology through mechanisms that differ from the single-target action of glyphosate. This underscores its potential for sustainable weed management.