The Study On Allelopathic Ecological Control Of Alien Plants Invading Common Plants In South China

In recent years,the invasion of alien plants took place frequently and seriously threatens the common ecological stability and biodiversity.Eliminating them with drugs will seriously pollute the water and soil while removing them with human hands costs a lot and cannot bring about eradication.Therefore,how to effectively use ecological methods to control alien invasive plants become a hot spot of present research.Mikania micrantha H.B.K.and Ipomoea cairica are the two major invasive alien plants and bring serious harm to the ecological environment in South China.Community reconstruction and allelopathic prevention and control are currently the two effective methods of ecological control put forward by the scholars after their research.Community reconstruction can solve the fundamental problem for good.It reconstructs the biological community so that it is in an advantageous position in interspecies competition and thus controls the alien plants.But it comes with a high cost and has slow effects.In allelopathic prevention and control with ecological safety as its aim,on one hand,we cultivate plants with allelopathy for direct prevention and control.O n the other hand,we extract,separate and identify allelopathic materials to develop eco-chemical reagents.These two methods are new in ecological prevention and control,but they are still in the phase of exploration and there has been little research.We now have reports on the successful use ofcommunity reconstruction in controlling Mikania micrantha H.B.K.However,there have been few reports on whether the reconstructed plants haveallelopathy,whether it is helpful to successfully control invasive plants.Whether the plants have stronger allelopathy after community reconstruction is worth exploration.From the perspective of allelopathy,this paper discusses the reason for the success of community reconstruction and chooses the plants that have,in practice,successfully controlled Mikania micrantha H.B.K.and Ipomoea cairica:Dicranopteris pedata,Acacia auriculaeformis,C innamomum burmamiand Melastoma malabathricum.Through simulation experiment with potted plants,it measures the influence of the water extracts of the four plants and their mixtures on Mikania micrantha H.B.K.and Ipomoea cairica,mainly including the influence of biomass allocation model,photosynthetic characteristics and allelopathy.It discusses the feasibility of using common plants to controlMikania micrantha H.B.K.and Ipomoea cairica.The results are:?1?Water extracts of the four plants and their mixtures have allelopathy on Mikania micrantha H.B.K and Ipomoea cairica;?2?the allelopathy increases with the increase of the concentration of the water extracts;?3?when the concentration of the mixtures is 200 mg·L^-1,the allelopathy on Mikania micrantha H.B.K and Ipomoea cairica is the strongest;?4?the total allelopathy of the community of the four plants is stronger than that of a single plant.The research shows that:the allelopathyof the mixed eluviation of the plant community simulated by the mixed water extracts has a stronger controlling effect than one single plant.It proves that the success of community reconstruction and the plants it uses is relevant with theallelopathic controlling effect on the invasive p lants—Mikania micrantha H.B.Kand Ipomoea cairica.Different plants have different allelopathic controlling effect.Therefore,choosing allelopathic plants to build natural communities and increase the diversity of community species can effectively prevent and control the invasion of alien plants.The results of this research can provide theoretical basis for plant community reconstruction,prevention and control of alien plants and the development of new bioherbicide.