AUTHORS: Csengele Barta, Missouri Western State University; Sonja Weber, Missouri Western State University; Rene Frye, Missouri Western State University; Teri Larison, Missouri Western State University; Angel Justus, Missouri Western State University
ABSTRACT: Velvet bean (Mucuna pruriens, VB) seeds were found to produce various allelopathic compounds that influence the growth of neighboring plants. Our laboratory’s prior research highlighted that VB seed coats release metabolites with negative, while the endosperm has positive allelopathic effects. We have demonstrated this effect in various species, including monocots and dicots. Through non-targeted metabolomic analysis of VB seed endosperm, L-Dopa (L-3,4-dihydroxyphenylalanine) emerged as a significant candidate among the potential allelochemicals. This study investigated the effects of L-Dopa on the growth and development of Brassica species. Our experiments demonstrated that low concentrations of L-Dopa (within 0.01-0.05 mg/mL) enhanced Brassica growth. Treated plants exhibited increased root and shoot length, enhanced biomass accumulation, and improved overall plant vigor compared to control groups. Notably, Brassica plants exposed to L-Dopa showed a marked increase in chlorophyll content, indicating enhanced photosynthetic capacity. Our findings suggest that L-Dopa, derived from VB seed endosperm, holds promise as a natural growth enhancer for Brassica crops. Its application could lead to more sustainable agricultural practices by reducing the reliance on synthetic growth regulators and fertilizers. Interestingly, the stimulatory effects of L-Dopa were, however, concentration-dependent. While low concentrations enhanced growth, higher concentrations exhibited inhibitory effects, consistent with the typical biphasic response of allelochemicals. This dual role underscores the importance of precise dosage in utilizing L-Dopa for agricultural applications. These insights into L-Dopa's allelopathic effects advance our understanding of plant-plant interactions and highlight the potential of natural compounds in improving crop productivity and sustainability. Future research will focus on elucidating the detailed molecular mechanisms of L-Dopa's action and exploring its potential benefits across different crop species.
