Research On An The Ecological Mechanisms Of Replacement Control Alternanthera Philoxeroides With Humulus Scandens

As one of the three major global environmental problems,invasive species have posed serious threats to native ecosystems,regional economies and so on.Based on various literature treatment methods of invasive plants,the prevention mechanism of replacement control of invasive weeds and selection methods of native plants in China have sufficiently been reviewed.Generally,microorganisms,animals,and chemicals in the soil are changed by native plants,which alter the environment of invasive plants.At the same time,native plants compete with invasive plants for resources such as nutrients and light energy,making invasive plants at a disadvantage.These studies may not only help us understand the underlying mechanism of exotic plants intensively,but also supply a scientific foundation of control current invasions and prevention of future invasions.Hydroponics were carried out in the form of single species and mixed seed,the morphological indexes and the chemical measurement characteristics of Alternanthera philoxeroides under the different N/P in April 2017.The results showed that In the 4:1 treatment,the nitrogen utilization rate of A.philoxeroides was significantly higher than that of other treatments.Under the medium nutrient conditions,the phosphorus utilization rate of the lotus grass decreased with the increase of N/P,and under the medium nutrient conditions,the attack power of A.philoxeroides was the greatest in the 2:1 treatment.Four treatments was setted,3:3,2:4,4:2,6:0 and 0:6 were planted in 4 proportions.The results showed that 4:2 treatment reduced the photosynthetic index of A.philoxeroides,and after June,the treatment significantly reduced the maximum net photosynthetic rate and daily net photosynthetic rate of lotus grass,and increased the plant’s midday depression.The total chlorophyll content of mixed species of A.philoxeroides was higher than that of single species,but the ratio of chlorophyll a to chlorophyll b was lower.The impacts of invasive plants are mediated by plant–microbe interactions.Ecologists are interested in the variance of the rhizosphere microbial community structure of invasive and native plants.To clarify the interaction mechanism between native and invasive plants,the characteristics of rhizosphere soil microbial communities of invasive plants under different degrees of replacement plant control were investigated.Rhizospheric soils of A.philoxeroides with different degrees of substitution with Humulus scandens(Lour.)Merr.(no replacement,low degree,high degree,replacement and CK using its coverage in the invaded ecosystems)were collected.Soil electrical conductance,pH,available phosphorus and available potassium were major factors controlling the rhizosphere microbial community structure of A.philoxeroides.Plant replacement significantly reduced the abundance of Acidobacteria and Verrucomicrobia,but not that of Chloroflexi and Actinobacteria.Low and high degrees of H.scandens replacement increased the richness of the soil fungal community.Overall,the results indicated that the rhizosphere microbial community was changed by replacement plants of this invader in novel environments and provides the theoretical basis for A.philoxeroides control.