入侵植物意大利苍耳和苍耳种间竞争能力的比较

Comparison of competitive ability between invasive plant Xanthium italicum and X.sibiricum

有研究表明意大利苍耳对入侵地的农业生产和畜牧业发展已造成了严重危害,然而有关其在自然群落中对本地植物影响的研究尚未见报道。故本研究以意大利苍耳和本地植物苍耳为试验材料,开展了种间竞争试验,研究了单种模式与混种模式下该两种植物生物量及种子产量的变化式样,以及二者的种间差异,并通过相对产量(RY)与竞争攻击系数(A)比较了二者种间竞争能力的相对强弱。结果表明:单种种植条件下意大利苍耳的根、茎、叶、果实与总生物量以及种子产量均显著高于苍耳,分别是苍耳的2.71、2.24、3.33、1.51、2.61和1.21倍。二者混种共存时,意大利苍耳的根、茎、叶、果实与总生物量以及种子产量分别是苍耳的6.38、2.98、5.39、2.76、3.98和1.72倍,说明混合种植条件下,意大利苍耳各器官的生物量及种子产量得到了显著提高和促进,而苍耳的生物量积累与种子产量却显著下降,这使得二者间的差异进一步加剧。相对产量(RY)和竞争攻击系数(A)的结果显示,共存条件下意大利苍耳的种间竞争能力显著高于苍耳。受意大利苍耳竞争抑制的影响,苍耳不仅营养生长受到了显著抑制、植株矮小,而且生殖生长也受到了强烈抑制、种子产量大幅下降,从而使苍耳的适合度显著降低。

Previous studies have shown that the invasive plant Xanthium italicum has caused substantial harm to agricultural production and animal husbandry development.However,research on the impact of this alien cocklebur on native plants in natural communities is limited.In this study,X.italicum and the native plant X.sibiricum were used as experimental materials.Interspecies competition experiments investigated the variations and interspecific differences in biomass and seed yield of each plant under monoculture and interplanting treatments of both species.The relative competitiveness of these species was compared using relative yield(RY)and aggressivity(A).The results showed that under monoculture conditions,the root,stem,leaf,fruit,total biomass,and seed yield of X.italicum were significantly higher than those of X.sibiricum,which were 2.71,2.23,3.32,1.51,2.61 and 1.21 times as high as those of the native plant,respectively.When the species were interplanted,the biomass of the roots,stems,leaves,fruits,total biomass,and seed number of X.italicum were 6.38,2.98,5.39,2.76,3.98,and 1.72 times higher than those of X.sibiricum,respectively.The results showed that under the interplanting condition,the biomass of each organ and the seed yield of X.italicum were further improved and promoted.In contrast,the individual biomass and seed yield of X.sibiricum decreased significantly,which further aggravated the differences between the two plants when interplanted.The RY and A results show that the interspecific competition ability of the invasive plant X.italicum was significantly higher than that of X.sibiricum.Under the competitive inhibition of the invader,the vegetative growth of the native plant was significantly suppressed,its reproductive growth strongly inhibited,and its seed yield decreased significantly.Moreover,its offspring abundance will be remarkably reduced in subsequent years.All these factors will result in a sharp reduction in the fitness of the native plant X.sibiricum in the natural community.