Abstract:

This experiment investigated the allelopathic effects of leachate from milkvetch （Astragalus sinicus） decay on seed germination and seedling growth of goosegrass （Eleusine indica）. The experiment treatments comprised different decomposition durations and different milkvetch decomposition leachate concentrations applied to seeds of goosegrass， and six physiological indexes such as germination rate were determined. The activities of protective enzymes and the contents of proline （Pro） and malondialdehyde （MDA） in the leaves of goosegrass were determined after root irrigation with different concentrations （2%， 5%， 30% and 80%） of milkvetch decomposition leachates. It was found that for a given concentration of decomposition leachates， the inhibition effect was more pronounced with greater decomposition duration. At low concentrations of decomposition leachate， a hormesis effect was observed. When the decomposition duration exceeded 2 days and the decomposition leachate concentration was 80% or more， seed germination was completely inhibited. Superoxide dismutase activity was decreased with increased leachate concentration. Peroxidase activity was lower at leachate concentrations below 30%， and higher at concentrations greater than 30%. Catalase activity was increased with increasing leachate concentration up to 30% and was decreased as leachate concentrations reached 80%. When the concentration of decomposition leachate applied was greater than 2%， the content of MDA， Pro and H₂O₂ in goosegrass leaves increased with the increase of leachate concentration. In conclusion， the decomposition leachate of milkvetch has significant inhibitory effects on the seed germination and seedling growth of goosegrass. It is concluded that milkvetch decomposition leachate has the potential to inhibit weed growth. This study provides reference information for research into allelopathically active substances in milkvetch.

Key words: milkvetch, goosegrass, decomposition leachate, weed suppression