3种恶性杂草对荞麦化感潜力的比较研究

Comparison of the Allelopathic Potential of Three Kinds of Noxious Weeds

辣子草(Galinsoga parviflora Cav.)、三叶鬼针草(Bidens pilosa L.)和土荆芥(Chenopodium ambro-sioides L.)是西南地区荞麦农田中常见的恶性杂草,分别采用培养皿滤纸法和盆栽试验,比较分析其水浸提液和凋落物覆盖对荞麦的化感潜力.试验显示:3种恶性杂草水浸提液和凋落物均显著抑制了荞麦的种子萌发(P<0.05),导致出苗困难,且具有浓度/质量依赖效应;辣子草和三叶鬼针草的水浸提液和凋落物对根长、干质量和鲜质量的影响表现“低促高抑”现象,而土荆芥则表现为浓度/质量依赖性下降;3种杂草的凋落物对苗高整体表现为抑制效应.结果表明,荞麦不同生长阶段对杂草化感作用的敏感性不同,以种子萌发期最为敏感,根系生长期次之;3种恶性杂草的化感效应强弱依次为三叶鬼针草>辣子草>土荆芥.

Galinsoga parviflora Cav.,Bidens pilosa L.and Chenopodium ambrosioides L.are common noxious weeds in buckwheat fields in southwestern of China.The differences of these weeds’allelopathic potentials on seed germination and seedling growth of buckwheat(Fagopyrum esculentum Moench)are studied by using the culture dish filter paper method and pot method,respectively.The results show that the aqueous extracts and the litters significantly inhibited the seed germination of buckwheat(P<0.05),and the results are difficulty in emergence and concentration/quality dependence.The root length,dry weight and fresh weight of buckwheat are promoted in low concentration and are inhibited in high concentration when treated by the aqueous extracts and the litters of G.parviflo-ra and B.pilosa,while these indicators show a concentration-dependent decline when treated by C.ambrosioides.On the whole,the effects of litter cover of three weeds on seedling height show inhibitory effects.These results suggest that the different growth stages of buckwheat had different sensitivities to these weeds’allelopathy,and the seed germination is most sensitive,followed by root elonga-tion,and the allelopathic effects of the three noxious weeds are in the order of B.pilosa>G.parviflora>C.ambrosioides.