Investigation on Non-coevolutionary Trends of the Invasive Plant Mikania micrantha and Its Neighbouring Species by Analyzing Their Intraspecific and Interspecific Allelopathy

Abstract:

In order to predict the non-coevolutionary trend between invasive species with their neighbor species, the seedlings of invasive species Mikania micrantha and three neighboring species, including Ipomoea cairica, Pueraria lobata and Paederia scandens were treated with aqueous leaf extracts, the allelopathic relationship between them were studied. The results showed that the allelopathic effects of M. micrantha on the neighboring species varied with SE=0.50, 0.61, -0.16 for I. cairica, Pueraria lobata and Paederia scandens, respectively, and there was a strong promoting allelopathic effect in intraspecific M. micrantha (SE=0.61), indicating its weak intraspecific competition. The allelopathic effect of intraspecific Pueraria lobata (SE=0.32) was weaker than that of M. micrantha (SE=0.61), and its interspecific allelopathic effect was similar to that of M. micrantha (SE=0.52, 0.50). The allelopathic effect of intraspecific I. cairica (SE=0.06) was weaker than that of M. micrantha and Pueraria lobata (SE=0.32), and its interspecific promoting effect (SE=0.24) was weaker than that of M. micrantha. The intra-and inter-specific allelopathy showed inhibiting effects in Paederia scandens (SE=-0.18, -0.07), demonstrating their strong intra-and inter-specific allelopathic competition. The distribution frequency and abundance of four species in the field were in the order as M. micrantha > Pueraria lobata > I. cairica > Paederia scandens, which is consistent with the results of the allelopathy competitiveness. Therefore, the intra-and inter-specific allelopathy play a very important role in the comprehensive competitiveness of invasive species with their neigboring plants, which sheds the lights on non-coevolutionary trends between the invasive species and their neighboring species.

Key words:Allelopathy;Invasive plant;Intra-specific relationship;Inter-specific relationship;Competitiveness;Non-coevolution