Study On The Interaction Between The Growth Of Invasive Plants And Soil Microorganisms In The East Of Guangdong Province

The invasion of exotic plants can cause the microbial community structure of soil intrusion,physicochemical properties and enzyme activity change,this change in turn will affect the growth of plants and the invasion of invasive plants and native plants competition,invasion of this new mechanism called the interaction mechanism of soil microbiology.Invasive plant and soil microbial community between the intrusion the interaction and feedback mechanism of exotic plant invasion has become a research important content and the international research focus.This study from the angle of ecology underground alien plant invasion mechanism through field sampling and greenhouse pot experiment to explore,for the effective prevention and control of alien invasive plants,to maintain the stability of the ecosystem to provide information.The main results are as follows:1 Effects of exotic plant invasion on Rhizosphere Soil Microbes1)Microbial culture results display.There were 33 PLFA biomarkers in studied soil plots,including PLFA marker 24 bacteria species,four actinobacterias,four fungus and one protozoa;The invasion of R.repens may have greatly changed the microbial community structure in soil.With the increasing of invasion R.repens,the relatively contents of bacteria,fungi,protozoa,and total PLFAs showed a trend of increasing.Meanwhile,compared with the non-invasive soil,content of some functional microorganism in soil with strong invasion,in which the content of Abuscular mycorrhizal fungi increased by 29.80%,that of Burkholderia and Hydrogenobacter increased by 18.25%and 11.57%,respectively,indicating that these functional microorganisms may play an important role on the invasion of R.repens.In addition,Shannon-wiener index and Margalef index displayed an increasing trend with increasing of invasion,and the Pielou index showed a decreasing trend.2)With the red hair grass invasion degree increase,soil total nitrogen,available nitrogen,available potassium content was increased.The total nitrogen increased 22.16%,nitrogen increased 70.51%,available potassium increased by 2.7%,while the available phosphorus content had no difference between soil;pH(P<0.01)and the water there are very significant differences,compared with the red hair Caofei invaded soil,heavily invaded soil pH increased by 15.09%,water content(F = 46.317,P<0.01)increased by 32.95%.3)With the colonization and invasion of R.repens,the content of microorganism in soil significantly increased,in which the relative content of bacteria were increased by 11.34%,fungi and protozoa increased by 19.60%and 13.95%,respectively.Compared with the non-invaded soil,the invertase activity in soil with mold invasive and strong invasive increased by 51.55%and 73.46%,urease activity increased by 12.80%and 68.60%respectively,however,catalase activity decreased by 22.5%and 59.33%,and cellulase activity had no or less change.4)There was a significant positive correlation between the content of bacteria,fungi actinobacteria,protozoa and the invertase,urease activities,but a negative correlation with catalase activity.In addition,there was a significant positive correlation between the fungi,protozoa and cellulase activity,and a negative correlation between bacteria,actinobacteria and cellulase activity.The settlement of R.repens could change the soil microbial community structure,enzyme activity and soil physical and chemical properties.2 Greenhouse pot experiment shows:The experiment indicated that the growth of the three plants described above was different in disparate soil.The strongest growth inhibition is W.trilobata in sterilization soil.Compared with the growth of plants in untreated soil,the plant height was decreased by 17.59%,the number of leaves decreased by 38.10%,biomass was reduced by 56.00%.The growth inhibition of S.nodiflora was the greatest in anti-fungal soil.Compared with the plant in untreated soil,the height,the number of leaves,biomass,the electron transfer rate of S.nodiflora was decreased by 42.28%,38.89%,16.99%,7.41%.The growth inhibition of S.nodiflora was also the greatest in anti-bacteria soil,compared with the growth in untreated soil,the plant height was decreased by 36.64%,the number of leaves was decreased by 38.89%,biomass was reduced by 33.67%,the electron transport rate increased by 11.11%.The soil without microbes has a strong inhibitory effect on the growth of W.trilobata.The growth of fungi and bacteria in the soil of S.nodiflora had obvious inhibitory effects.The soil invaded by W.trilobata is not only suitable for W.trilobata's growth,but also for its companion S.nodiflora's growth.However,it has little effect on the D.chinensis.3 Competition experiments show:The relative competitive advantage of moist heat sterilization soil decreased from 65.65%to 50.58%when W.trilobata and D.chinensis mixed planting.The relative competitive advantage of moist heat sterilization soil decreased from 53.87%to 40.92%when W.trilobata and S.nodiflora mixed.The promoting effect of microorganism is obvious when invasive plant W.trilobata associated plant competition growth.The results also show that W.trilobata in four kinds of soil in height and biomass were a single value is higher than the mixed planting.That kind of associated(D.chinensis and S.nodiflora)inhibition of W.trilobata growth.This study further confirmed that the soil microbial community is conducive to promoting competition with W.trilobata.