薇甘菊叶片水提液对土壤钾素活化及酶活性的影响

为探究薇甘菊(Mikania micrantha H.B.K.)的化感作用, 通过盆栽实验, 研究了不同质量浓度的薇甘菊叶片水提液对薇甘菊及其伴生植物火炭母(Polygonum chinense)根际土壤钾素活化及土壤酶活性的影响.研究结果显示:薇甘菊叶片水提液显著提高了薇甘菊根际土壤的脱氢酶与β-葡糖苷酶活性; 在薇甘菊单种中, 当叶片水提液质量浓度为15.00 g/L时, 薇甘菊的根际土壤速效钾的质量分数是对照(0 g/L)的2.53倍; 而薇甘菊叶片水提液也显著增加了火炭母根际土壤的脱氢酶与β-葡糖苷酶活性; 当叶片水提液质量浓度为15.00 g/L时, 火炭母根际土壤速效钾的质量分数增加了2.03倍, 但其火炭母的地上部分生物量及其钾的质量分数显著下降.上述结果表明:薇甘菊叶片水提液能增强自身根际土壤的酶活性, 并且加速土壤钾养分活化; 但薇甘菊叶片水提液的化感物质可能对火炭母的生长具有抑制作用.这表明薇甘菊化感作用对其入侵具有重要作用.

Effects of Leaf Leachates of the Invasive Plant Mikania micrantha H.B.K. on Soil Potassium Activation and Soil Enzyme Activity

To investigate the allelopathy of Mikania micrantha H.B.K. (M. micrantha), a pot experiment was conducted to study the effects of leaf leachates of M. micrantha at different concentrations on rhizosphere soil potassium activation and soil enzyme activity of M. micrantha and the co-occurring plant, Polygonum chinense (P. chinense). The results showed that leaf leachates of M. micrantha increased the activity of dehydrogenase and β-glucosidase in rhizosphere soil of M. micrantha. And in M. micrantha monoculture, available potassium content in rhizosphere soil was 2.53 times higher than those of the control (0 g/L), when the leaf leachates concentration of M. micrantha was 15.00 g/L. In the meanwhile, leaf leachates of M. micrantha also increased the activity of dehydrogenase and β-glucosidase in rhizosphere soil of P. chinense. And in P. chinense monoculture, available potassium in rhizosphere soil increased by 2.03 times, and the aboveground biomass and the potassium of aboveground biomass decreased significantly at 15.00 g/L leaf leachates of M. micrantha. Our results suggested that allelochemicals of leaf leachates of M. micrantha could enhance the activity of soil enzymes and accelerate the activation of soil nutrient. But allelochemicals in leaf leachates of M. micrantha may inhibit the growth of P. chinense. The results may indicate that the allelopathy of M. micrantha plays an important role in its invasion.