Study On The Community And Habitat Factors Analysis Of The Invaded Land By Solidago Canadensis L.

The mechanism of plant invasion has been one of the focuses of intrusion ecology,and the invasive plants have been able to survive,reproduce and spread rapidly in the invading areas due to the lack of natural enemies and environmental suitability,resulting in the decline of local species diversity and ecological function.At present,the study on the decline of local species diversity caused by invasive plants is mainly focused on the species diversity of plant communities,soil fauna and microbial species diversity,and the impact of invasiveplants onpotential vegetation communities is rare.Invasive plants tend to improve their competitiveness by altering their shape,and can also promote their growth and inhibit the growth of other plants by releasing allelopathy.The invasion success of exotic plants is often closely related to the habitat factor of invasive region by S canadensis L.is one of the main invasive plants in China,the study shows that its invasion has negative effects on the local plant community,soil fauna and micro-biodiversity,and the extracts from Solidago canadensis plants have inhibitory effects on the growth of some plants,The invasion was related to the local soil nutrients,climate,elevation and other factors.However,there are few reports on the allelopathy of S canadensis L.,the main factors affecting the success of the invasion and the influence on the potential plant communities.In this paper,through field investigation and laboratory tests,the effect of the invasion of S canadensis L.on the plant community in soil seed bank and the effect of its litter on the seed germination and seedling growth of three species of plants were investigated.The invasion and habitat factors of a yellow flower in Canada were investigated by field investigation and the sub-relations are studied and analyzed,The results are as follows:1)In order to study the effects of S.canadensis L.on the soil seed bank,the field vegetation investigation and the experiment of indoor seed germination were carried out and founded that the area of invasived by S.canadensis L.included 21 species,21 genera,13 families,and the uninvasived area included 31 species,28 genera,18 families,main covering Gramineae,Compositae,Moraceae,Solanaceae,Rosaceae,etc.and there was no significant difference between diversity index and dominance index,but there was significant difference between evenness and richness.The seedbank of invasived by S.canadensis L.covered by 30 species,28 genera,17 families,uninvasied seedbank included 27 species,27 genera,16 families,main including Compositae,Gramineae,Caryophyllaceae,and there is no difference among the indicators.The number of species and the total number of plants in soil seed bank were significantly different between 0-5cm and 5-10 cm.2)In order to analyze allelopathy effects of the litter of S.canadensis L.on other plants,extraction of Physico-allelopathic substances from the litter by Water leaching,studied the effect of the extraction solution of different concentration on germination and seedling growth of L perenne L.,F elata Keng ex E.Alexeev and T erecta L.The results show that:1)Under the same concentration of extract,the germination rate of T erecta L was 29.2-51.7%.Lower than the others;2)The leachate of litterp romoted the height of seedling of L perenne L.and F elata(RI> 0),however,the height of seedling of T erecta L restrained with the increase of extract concentration;3)the concentration of leachate is lower(0.025g/ml),promoted the root length of three kinds of plants;restrained the length at the higher level(0.075g/ml).3)In order to study the relationship between S canadensis L.and habitat factors,the field investigation of habitat factors of S.canadensis L.was carried out,and the correlation and principal component analysis of the collected data were carried out.The results are as follows:the frequency of S.canadensis L.in Canada and the total plant number of available potassium and sample land,total phosphorus,weed coverage,organic matter,plant species number,elevation,slope,arbor height,average plant height of S.canadensis L.,arbor size,soil moisture content,water source distance,soil available phosphorus and other ecological factors showed positive corretion.with weeds height,arable land distance,Soil ph showed negative correlation.