豚草和三裂叶豚草拮抗植物的筛选

【目的】 研究豚草(Ambrosia artemisiifolia L.)和三裂叶豚草(Ambrosia trifida L.)浸提液对常用替代牧草高羊茅、早熟禾、黑麦草、披碱草,以及对苜蓿、葵花、玉米、小麦、甜菜种子萌发的影响;筛选对豚草和三裂叶豚草具有防控效果的替代植物以及最佳混种方式。【方法】 采用培养皿滤纸法,研究豚草和三裂叶豚草浸提液对供试种子萌发的影响。采用盆栽竞争试验,运用DeWit取代试验研究法,设置牧草和入侵杂草5种混种方式,混种比例分别为1∶1、1∶2、1∶3、2∶1、3∶1,研究黑麦草、披碱草和高羊茅与豚草和三裂叶豚草的竞争效应,分析3种牧草对豚草和三裂叶豚草的替代控制潜力。【结果】 随着豚草和三裂叶豚草的浸提液浓度的增加,4种常用替代牧草种子和新源县5种主要作物种子发芽率,发芽指数和化感效应指数均下降。5种混种密度下,黑麦草、高羊茅与三裂叶豚草混种比例为3∶1时,三裂叶豚草的竞争平衡指数分别为(-0.505 1±0.301 5)、(-0.757 6±0.265 88)均显著小于0(P<0.05);黑麦草、高羊茅与豚草混种比例为1:3时豚草竞争平衡指数分别为(-0.955 8±0.518 08)、(-2.049 7±0.178 55)均显著小于0(P<0.05)。【结论】 豚草和三裂叶豚草浸提液对供试种子萌发具有化感抑制作用;且浸提液浓度越大抑制作用越强,同时叶部化感抑制作用大于根部。三裂叶豚草对四种牧草种子萌发的化感抑制作用大于豚草。黑麦草和高羊茅可以作为豚草和三裂叶豚草的替代植物。黑麦草和高羊茅防治三裂叶豚草时建议播种比例为3∶1;防治豚草时建议播种比例为1∶3。豚草和三裂叶豚草发生密度较大时其化感抑制作用越强,影响牧草萌发生长,应适当加大替代牧草播种量。

Screening of Antagonistic Plants: Ragweed and Giant Ragweed

【Objective】 To study the effects of extracts of ragweed and giant ragweed on seed germination of common alternative forages tall fescue, Kentucky bluegrass, ryegrass and Elymus, as well as alfalfa, sunflower, corn, wheat and sugar beet in order to screen the alternative plants with control effect on ragweed and giant ragweed and the best mixed painting method.【Methods】 The effect of ragweed and giant ragweed extract on seed germination was studied by using petri dish filter paper. A pot competition experiment was conducted, and DeWit was used to replace the experimental method to set up five mixed methods of herbage and invasive weeds, whose ratios were 1:1, 1:2, 1:3, 2:1 and 3:1, respectively. The competition effects of Ryegrass, Elymus dahuricus and Festuca Elata with ragweed and giant ragweed were studied to identify the potential of the three forages for the control of ragweed and giant ragweed.【Results】 With the increase of the extract concentration of ragweed and giant ragweed, the germination rate, germination index and allelopathic index of the 4 common substitute forage seeds and the 5 common crop seeds in Xinyuan County decreased on average. Under the 5 mixed densities, when the mixed ratio of ryegrass, tall fescue and giant ragweed was 3:1, the comparison indexes of giant ragweed were (-0.505,1±0.301,5) and (-0.757,6±0.265,88) respectively, which were both significant lower than 0 (P<0.05); When the ratios of ryegrass, tall fescue and ragweed were 1:3, the ragweed competition balance index was (-0.955,8±0.518,08) and (-2.049,7±0.178,55), which were significantly lower than 0 (P<0.05); Under the mixed ratios of Elymus triloba and ragweed and giant ragweed, there was no significant difference in the comparative balance index between ragweed and giant ragweed from 0 (P<0.05).【Conclusion】 The extracts of ragweed and giant ragweed showed allelopathic inhibition on seed germination, and the higher the concentration of the extracts, the stronger the inhibition. At the same time, the allelopathic effect of leaf was greater than that of root. The allelopathic effect of giant ragweed on seed germination of four forage grasses was stronger than that of ragweed. Ryegrass and tall fescue could be used as substitutes for ragweed and giant ragweed. Ryegrass and tall fescue have a recommended ratio of 3:1 for giant ragweed and 1:3 for ragweed. Considering that when the density of ragweed and giant ragweed is higher, the allelopathic inhibitory effect will be stronger, they will affect the germination and growth of forage, so the sowing amount of substitute forage should be increased appropriately.