Effects Of AMF And Litter On The Competition Of Intraspecific And Interspecific Nutrient Between Broussonetia Papyrifera And Carpinus Pubescens

Arbuscular mycorrrhizal fungi(AMF)is an endophytic mycorrhizal fungi widely existing in various terrestrial ecosystems,which can form symbionts with most plants,and its mycorrhizal fungi have the function of promoting plants to absorb mineral nutrients such as nitrogen,phosphorus and kalium to promote plant growth.As the main source of organic matter in the forest ecosystem,litter decomposition plays an important role in the material circulation and energy flow of the ecosystem.Previous studies have shown that AMF can promote the decomposition of litter.Highly heterogeneous karst habitats maintain high species diversity.How to coexist with karst organisms in intraspecies and interspecific competition,whether there are differences in growth traits and nutrient element distribution under AMF inoculation and litter addition conditions? Therefore,this experiment with karst suitable tree species Broussonetia papyrifera and Carpinus pubescens as test objects to study intraspecific and interspecific competition under the condition of adding litter and inoculation of AMF on karst plants' growth characteristics,nutrient uptake and ecological characteristics of chemical measurement by the same(intraspecific competition)and heterogeneous(interspecific competition)planting,which is of great significance in clarifing the function relation between the karst habitat of plants about species coexistence mechanisms,mycorrhizal symbiosis and litter decomposition.In this experiment,the plants were planted with both intraspecific and interspecific hybrids factor,the AMF factor and litter factor were inoculated to carry out the three-factor indoor control experiment.We measured growth indexes such as seedling height,ground diameter and biomass,as well as nutrition elements nitrogen,phosphorus and kalium after the plants were planted for half a year.The main results are as follows:(1)Inoculation of AMF can significantly increase the seedling height,ground diameter and leaf area of B.papyrifera,and reduce the phenotypic growth characters of C.pubescens.Under the condition of intraspecific competition,the addition of litter increased the fungal infection rate of B.papyrifera and C.pubescens.Under the condition of interspecific competition,the addition of litter increased the fungal infection rate of B.papyrifera and reduced the fungal infection rate of C.pubescens.Inoculation of AMF can improve different level broussonetia papyrifera root indicators and plant roots,stems,leaves and total biomass except for root average diameter.Each treatments reduced the root indicators of B.papyrifera except root average diameter,reducing the plant roots and total biomass accumulation as well.Inoculated AMF increased the root-shoot ratio and the high-diameter ratio of B.papyrifera and decreased the root-shoot ratio and the high-diameter ratio of C.pubescens.The growth characters of seedlings of two plants were lower than that of interspecific competition under the condition of intraspecific competition.(2)Inoculation of AMF significantly increased the uptake of total N,P and K in the roots,stems and leaves of B.papyrifera,increasing the uptake of nitrogen in the roots and stems anddecreased the uptake of total P and K in various organs of C.pubescens.Addition of litter can reduce the N uptake of B.papyrifera and C.pubescens except for increasing the root and total N uptake of C.pubescens under inoculation of AMF treatment.Except the addition of litter increased the P uptake in leaves under inoculation of AMF treatment,the addition of litter reduced the P uptake in various organs of B.papyrifera and C.pubescens.The addition of litter can reduce the K uptake in various organs of B.papyrifera and C.pubescens.The N,P and K nutrient uptake of the seedlings were lower than that of interspecific competition under the condition of intraspecific competition.(3)Inoculation of AMF can reduce the N:P,N:K,P:K and N:P:K ratios in the roots,stems and leaves of B.papyrifera,and improve the stoichiometric ratio of each organ of C.pubescens.Litter was added to increase the stoichiometric ratio of each organ of B.papyrifera,and increase the root stoichiometric ratio of C.pubescens.Litter was added to reduce the stoichiometric ratio in the inoculation of AMF treatment and increase the stoichiometric ratio in the unvaccinated AMF treatment in the influence of each stem and leaf in C.pubescens.The stoichiometric ratio of each organ of two plants seedlings are different under the conditions of intraspecific and interspecific competition.In general,the inoculation of AMF can significantly promote the growth of plants with strong mycorrhizal dependence,improve the uptake of N,P and K nutrient elements,and adjust the element distribution ratio in plants.For plants with weak mycorrhizal dependence,the inoculation of AMF will inhibit their growth and development.Litter addition had inhibitory effect on seedling growth and nutrient uptake and had some effect on plant nutrient regulation,the difference was not significant.Compared with intraspecific competition,intraspecific competition is helpful for plant growth and nutrient uptake,and the competition ability of plants under intraspecific competition can be significantly improved after AMF inoculation.