Effects Of Chaetomium Globosmn ND35 On The Drought Resistance Of Catalpa Bungei Seedlings And Soil Fertility

The development of mining had led a series of ecological problems,such as the pollution of the environment,degeneration of vegetation,decline of biodiversity and land productivity decline,which had threatened people's life.There were a large number of engineering measures had been implemented in the ecological restoration of abandoned lands at present,while the effect was not obvious.The poor soil water-holding capacity and low nutrient content were the main limiting factors during vegetation restoration.So the key to recover vegetation successly was how to improve soil water holding capacity and nutrient content.The active strains of microbial agents could improve the soil structure,fertility,water holding capacity and the microbial structure effectively after colonization in the soil.So it had a broad application prospect in the ecological reconstruction of abandoned mining lands.The C.globosmn ND35 has been proven to be able to improve the drought resistance of gramineous plants and cash crops by ameliorating soil fertility effectively.Which could provide a theoretical basis for the using of C.globosmn ND35 on ecological restoration at abandoned mining lands.However it is still unclear that the C.globosmn ND35 how to effect the drought resistance of arbor plant and the bacterial community structure of soil.Therefore,the C.globosmn ND35 and Catalpa bungei were chosen as the research object in this study.Firstly four treatments were designed and labeled as CK,T1,T2,T3.We screened the optimum application rate which was used in drought stress tests by analyzing the changes of C.bungei growth and soil fertility under different treatments.Then the drought stress test was designed which contained three moisture gradient and two bacteria agent content.In which we explored the effects of C.globosmn ND35 drought resistance of C.bungei.At the same time,the effect of C.globosmn ND35 on rhizosphere soil fertility,enzyme activities and microbial population was analyzed.Through this study,we hope to provide theoretical support for the application of C.globosmn ND35 on vegetation restoration.The main research results are as follows:1.Effects of C.globosmn ND35 on the growth of C.bungei seedingsThe application of C.globosmn ND35 could promote the growth of C.bungei seedlings significantly.The membership function indices of CK,T1,T2,T3 was 0.45,0.43,0.41 and0.40,respectively.Therefore,the C.bungei owned best growth under T2 treatment.2.Effects of C.globosmn ND35 on the physiological and biochemical indexes of C.bungei seedingsThe net photosynthetic rate(P_n)and biomass accumulation of C.bungei seedlings were significantly increased by 9.04%~41.50%and 26.46%~69.42%under the drought stress(P<0.05).Meanwhile the stomatal conductance(G_s),water use efficiency(WUE),transpiration rate(T_r),maximum photochemical quantity(F_v/F_m)of photosystem II,photochemical quenching(qP)and the electron transfer rate(ETR)of C.bungei seedlings were also significantly increased(P<0.05).The activity of peroxidase(POD)of C.bungei was significantly increased by 25.26%on the tenth day of water stress(P<0.05),but the effect was no longer significant with the extension of drought stress time.On the 30th day of stress,the application of the microbial agent could maintain the normal heat dissipation mechanism and prevent the damage caused by the accumulation of light energy to the photosystem II reaction center by improving the non-photochemical quenching coefficient(NPQ)of C.bungei seedlings under severe water stress.At the same time,it could promote the absorption of P element in stems and leaves of C.bungei seedlings under water stress.3.Effects of C.globosmn ND35 on soil fertilityThe application of C.globosmn ND35 could increase the content of organic matter,ammonia nitrogen and the activity of soil urease,sucrase and alkaline phosphatase significantly in gradient test(P<0.05).And the soil quality index(SQI)of CK,T1,T2,T3were 0.656,0.576,0.447 and 0.391,respectively.The content of soil organic matter and ammonia nitrogen could be significantly increased under water stress,and the catalase activity was also significantly increased by 4.21%~7.12%(P<0.05).At the same time,C.globosmn ND35 could significantly affect the distribution of bacterial communities in the soil,increase the number and the diversity of bacterial in the soil.While the effect on the amount of fungi was related to soil water content.The C.globosmn ND35 could promote the growth of C.bungei seedlings by improving the fertility,enzyme activity and micro ecological environment of rhizosphere soil.Meanwhile,it could alleviate the physiological and biochemical characteristics,water and nutrient utilization efficiency of C.bungei seedlings under drought stress.Therefore,the C.globosmn ND35 microbial agent will have broad application prospects on the vegetation restoration of degraded ecosystems such as abandoned mining lands in the future.