LAUSR

BACKGROUND Velvetleaf (Abutilon theophrasti Medik.), primarily a cropland weed, exerts adverse impacts on the productivity of various crops including soybean (Glycine max L.), wheat (Triticum aestivum L.), and maize (Zea mays L.) by hindering their vegetative growth. However, the interference mechanism of velvetleaf on the three crops remains unclear. RESULTS The inhibitory effect of velvetleaf water extract on the germination and growth of soybean, wheat, and maize was determined in pot experiments and field trials. Four phenolic acids: protocatechuic acid (PA), gallic acid (GA), chlorogenic acid (CHA), and vanillic acid (VA) were identified as allelochemicals. These allelochemicals were detected in different parts (leaves, roots, and stems) of velvetleaf, and in the rhizosphere soil of tested crops over the range of 1.19-556.23 μM kg -1 . These allelochemicals were administered in approximate concentrations as in velvetleaf roots and rhizosphere soil, and their effects varied with crop species and velvetleaf parts. The allelochemicals generally had low-dose stimulation and high-dose inhibition effects on the growth of soybean, wheat, and maize. Besides, the biomass distribution of these crops was affected by allelochemicals in the soil. In field trials, the allelochemicals significantly (P < 0.05) inhibited the growth of all tested crops over the whole growth period, and PA showed significant (P < 0.05) inhibitory effect on the yield of soybean, wheat, and maize. CONCLUSION GA, PA, CHA and VA in velvetleaf aqueous extracts were identified as allelochemicals which play an inhibition role on three crops. This article is protected by copyright. All rights reserved.