The Allelopathic Mechanism And Risk Analysis For Solidago Canadensis L.

More and more studies show that invasion of alien plants has caused severe impacts on native biodiversity. Solidago canadensisis L.is native to North America, which was introduced into China as ornamental plant in 1935, now it is one of the alien and detrimental species. Studies show that Solidago canadensis L. has allelopathic effects. Studies on allelopathic activity of Solidago canadensis L. on native plants grown should be valuable for understanding the mechanisms in chemical ecology that alien plants can successfully invade in a native ecosystem. And Studies on the pest risk analysis showed that the risk level of Solidago canadensis L.in China.The allelopathy of Solidago canadensis L. on receiver materials was studied by bioassay. The results showed that growth of receiver materials was restrained Solidago canadensis L., the allelopathic inhibitory effect of the aqueous extracts from Solidago canadensis L. was enhanced with the increase of its concentration. Receiver material for further study was selected with integrate subjection value, which was Triticum aestivum .The sequence of receiver materials' root allelopathy was Triticum aestivum> Raphanus sativus L.> Lactuce indica > Brassica chinensis > Brassica oleracea var. botrytis > Phaseolus radiatus L..The sequence of receiver materials' top allelopathy was Triticum aestivum > Brassica chinensis > Lactuce indica> Phaseolus radiatus L.> Brassica oleracea var. botrytis >Raphanus sativus L.From the protein content of the plant seedling, activities of the peroxidese(POD), catalase(CAT), superoxide dismutase(SOD) the plant seedling showed that the aqueous extract of Solidago canadensisis L.have different influences on different biochemical index of the seedling of the wheat. Among them, the aqueous extract of Solidago canadensisis L. have greater influence to the biochemical indexes of seedling of wheat. The soluble protein content and chlorophyll contents was reduced, the activities of POD,CAT,SOD were increased, the carotenoid contents was increased, the root activity was reduced, the dry matter weight of wheat and the N,P,K contents were also reduced, the MDA contents was increased. So, the aqueous extract of Solidago canadensisis L. have strong allelopathy to the wheat, and it is show as inhibiting effect. Allelopathy and competition separation-based bioassay approach was used to discuss the reaction of Solidago canadensis L. under different nitrogen supplies. The results showed that the invasive plant Solidago canadensis L. had a higher ability in interfering target plant wheat, represented by its stable and higher ability in resources competition as well as its increasing allelopathic potential in suppressing wheat when the nitrogen supply decreased in the co-cultured system.Considering the characteristics of Solidago canadensis L., the risk analysis index system and criterion model of Solidago canadensis L. was established, abiding by the pest risk analysis (PRA) criterion which was formulated by Food and Agriculture Organization (FAO) and International Plant Protection Convention (IPPC). Calculation model of the judgement first and second grade estimation criterion was established by the method of comprehansive multi-index evaluation. The results of the risk analysis showed that the risk level of Solidago canadensis L. was 2.15 which has reached the risk level of quarantine pest. So the pest should be added to the sheet of quarantine pests. At the same time, the risk management for control of Solidago canadensis L. was also evaluated in this paper, and all the results will be benefit for phytosanitary department to as a reference.