紫云英腐解液对牛筋草种子萌发及幼苗生长的影响

Effects of milkvetch(Astragalus sinicus)decomposition leachates on germination and seedling growth of goosegrass(Eleusine indica)

为探讨不同腐解天数及不同浓度梯度紫云英的腐解液对牛筋草种子萌发及二叶期幼苗生长的影响,以牛筋草种子为材料进行发芽试验,测定发芽率等6个生理指标。采用不同浓度的紫云英腐解液对二叶期幼苗进行灌根处理,测定牛筋草叶片的保护酶活性、脯氨酸(Pro)和丙二醛(MDA)含量。结果表明:相同浓度腐解液处理条件下,随着腐解天数的增加,腐解液对牛筋草的抑制作用增强;腐解液对牛筋草的化感作用存在“低促高抑”的现象;当腐解时间超过2 d,腐解液处理浓度达到80%时,能100%抑制牛筋草种子萌发。牛筋草幼苗的超氧化物歧化酶(SOD)活性随着腐解液浓度升高而下降;过氧化物酶(POD)在低浓度腐解液处理时酶活性下降,浓度大于30%时酶活性升高;过氧化氢酶(CAT)活性在30%腐解液浓度内随着浓度升高而升高,80%时活性下降。当腐解液浓度≥2%时,随着腐解液浓度的增加,牛筋草叶片MDA、Pro及过氧化氢(H_(2)O_(2))含量增加。综上所述,紫云英腐解液对牛筋草种子萌发及幼苗生长具有显著的抑制作用。由此可见,紫云英腐解物具有抑制杂草生长的潜力,研究结果可为发掘紫云英中抗杂草活性物质提供参考。

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 H_(2)O_(2)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.