两种本地植物种子萌发对飞机草的化感耐受性及其相互竞争

为探讨本地物种假地豆和白饭树对入侵植物飞机草的替代控制潜力,利用培养皿法和同质园种植实验分别研究了两个本地物种种子萌发对飞机草的化感耐受性及其与飞机草的竞争关系。结果显示:除了假地豆的萌发率在高浓度(2.5%)的飞机草叶提取液下受到显著抑制外,两个本地种的萌发在不同浓度飞机草根、茎、叶提取液下均不受抑制。飞机草与假地豆混种时,飞机草的株高、地下生物量比及根冠比显著降低,假地豆的株高无显著变化,但生物量显著增加;飞机草的竞争参数相对产量(RY)显著小于1,竞争攻击力系数显著小于零,表明其竞争力弱于假地豆。飞机草与白饭树混种时,飞机草的根冠比也显著降低,但株高和生物量均显著增加,而白饭树的株高和生物量却显著降低;飞机草的相对产量(RY)显著大于1,竞争攻击力系数显著大于零,表明其竞争力强于白饭树。结合以上结果,本地植物假地豆可以一定程度上竞争抑制飞机草的生长,具有替代控制飞机草的潜力,而白饭树可以在清除飞机草后的入侵地辅助植被修复。实验结果为飞机草替代控制的目标物种的筛选提供了科学依据,对被飞机草入侵生境生物多样性的恢复和重建具有一定指导意义。

Tolerance of seed germination in two native species to the allelopathic effect of Chromolaena odorata and the competition between them

To explore the potential of native species Desmodium heterocarpon and Flueggea virosa for replacement control of the invasive plant Chromolaena odorata, we assessed the tolerance of seed germination in the two native species to the allelopathic effect of the invasive species C. odorata and the competition among them via the culture dish method and a common garden pot experiment, respectively. Seed germination of the two native species was not inhibited at different concentrations of C.odorada root, stem, and leaf water leachate, except that 2.5% leaf leachate inhibited seed germination in D.heterocarpon. When the invader was grown with D.heterocarpon, plant height, underground biomass ratio, and the root/shoot ratio of C.odorada were significantly reduced, while those of D.heterocarpon remained unaffected. Furthermore, the total biomass of D.heterocarpon increased significantly compared to the control. Meanwhile, for C.odorada, the competition parameter relative yield (RY) was less than 1, and the competitive aggressivity coefficient was less than 0, indicating that the competitive ability of C.odorada was less than that of the native plant D.heterocarpon. When the invasive species was grown with Flueggea virosa, the root/shoot ratio decreased; however, plant height and total biomass of C.odorada increased significantly, while the plant height and total biomass of F. virosa decreased markedly. Moreover, the competition parameter RY and the competitive aggressivity coefficient of C.odorada were significantly greater than 1 and 0, respectively. These results indicate that the competitive ability of C.odorada was greater than that of native F. virosa. Furthermore, native D.heterocarpon may compete with the growth of the invasive species C.odorada to a certain degree, potentially serving as one of the objective plants for replacement control of the invasive species. Although the other native F. virosais not quite fit for direct control of the invasive species, it may be used to restore vegetation in the region wherein the invader was eliminated. These results provide a scientific basis for selecting objective species for replacement control of invasive C.odorada, guiding the recovery of biodiversity and renewal of invaded regions by C.odorada.