Diversity Of Arbuscular Mycorrhizal Fungi Of Camellia Oleifera And Its Effect On Absorption Of Organic Phosphorus

In this study,Camellia oleifera Abel.was used as the research object.The high-throughput sequencing?Illumina Miseq?technique was used to explore the community composition and species diversity of arbuscular mycorrhizal?AM?fungi in different strains of C.oleifera.A pot experiment was conducted to evaluate the effects of AM fungi on the growth,photosynthesis,root architecture,phosphorus uptake of C.oleifera and enzyme activities in the soil under different organic phosphorus levels,and analyzed the physiological and biochemical mechanisms of AM fungi to enhance the absorption of organic phosphorus in C.oleifera.The results of this study can provide reference for AM fungi in the absorption and utilization of soil nutrients in Camellia oleifera,and provide a scientific theoretical basis for the application of AM fungi to solve the problem of low phosphorus stress in high yield and stable yield of intensive Camellia oleifera.The main conclusions are as follows:1.Diversity of AM fungi community in different strains of C.oleiferaThe AM infection rate in the roots of different strains of C.oleifera was different.The infection rate from high to low was found in Ganxing 48?GX48?>Changlin 4?CL4?>Changlin 3?CL3?>Changlin 53?CL53?>Ganwu848?GW84-8?.A total of 1 phylum,1class,4 orders,10 families,12 genera of AM fungi were identified from the rhizosphere soil of 5 C.oleifera strains.And Glomus?41.05%?,Paraglimus?25.32%?,Claroideoglomus?21.28%?,Archaeospora?2.22%?and Ambispora?2.05%?are the top five genera with the highest abundance.The relative abundance of each AM fungi genus in different C.oleifera strains was different.The abundance of Paraglomus in GW84-8 strain was significantly lower than that in other strains,whereas the abundance of Glomus in GW84-8 strain was significantly higher than that in other strains?except for CL3?.Glomus,Paraglomus and Claroideoglomus are the dominant genera of 5 strains.There was no significant difference in the Alpha diversity index of AM fungal communities among different C.oleifera strains.The community structure of AM fungi in different C.oleifera strains is significantly different.Nitrate nitrogen is a significant soil factor affecting in AM fungal communities distribution.2.Effects of AM fungi and organic phosphorus on the growth and photosynthetic characteristics of C.oleiferaThe results of pot experiment showed that a good mycorrhizal structure was formed between Funneliformis mosseae and C.oleifera,and the type of infection structure within root was affected by the season.In August,the main type of infection structure was hypha,and in December,the main type of infection structure was vesicles and arbuscules.In August,the hypha colonization rate in treatment inoculated with AM fungi and treatment both inoculated with AM fungi and applied organic phosphorus accounted for 82.03%and91.27%of the total infection rate,respectively.In December,the sum of vesicle and arbuscule infection rate of treatment inoculated with AM fungi accounted for 79.65%of the total infection rate,while the sum of vesicle and arbuscule infection rate of treatment both inoculated with AM fungi and organic phosphorus accounted for 90.49%of the total infection rate.In the two measurement periods,the effectiveness of treatment inoculated with AM fungi was better than that of non-inoculation treatment.Under the same organic phosphorus level,inoculation of AM fungi increased the biomass,chlorophyll content,PSII primary light energy conversion efficiency,PSII actual photochemical efficiency and photochemical quenching coefficient,and reduced the non-photochemical quenching coefficient,indicating that the inoculation of AM fungi could increase the ability of absorbing light energy by C.oleifera leaves,enhance the activity of PSII reaction center,improve the transmission and utilization efficiency of light energy by C.oleifera.At the same level of organic phosphorus,the net photosynthetic rate,stomatal conductance and transpiration rate of C.oleifera inoculated with AM fungi were higher than those without inoculation,while the intercellular CO₂ concentration was significantly decreased,indicating that inoculation of AM fungi could enhance the photosynthetic capacity of C.oleifera,and subsequently promoting the growth and biomass accumulation of C.oleifera.In addition,the treatment both applied organic phosphorus and inoculated with AM fungal was more effective than other treatments in increasing the growth and photosynthetic capacity of C.oleifera.,indicating that there was a significant interaction between the application of organic phosphorus and inoculation of AM fungi,thus promoting the absorption and utilization of organophosphate by C.oleifera.3.Effects of AM fungi and organic phosphorus on root architecture,phosphorus uptake and matrix enzyme activities of C.oleiferaThe C.oleifera and matrix samples were collected in August and December respectively,and the results from these two periods showed similar trend.The organophosphorus-application treatment increased the content of organic phosphorus and available phosphorus of matrix,and the content of phosphorus of plant,indicating that the C.oleifera can utilize organic phosphorus.Under the same level of organic phosphorus,inoculation of AM fungi increased the total root length,root diameter,root volume,root surface area and root activity of C.oleifera,enhanced the phosphatase and phytase activities of C.oleifera and matrix,decreased the content of matrix organic phosphorus and available phosphorus,and increased the shoot and root phosphorus content,indicating that AM fungi enhanced the absorption capacity of C.oleifera for soil phosphorus.The treatment both inoculated with AM fungi and applied organic phosphorus was more effective than other treatments,indicating that AM fungi promoted the transformation of soil organic phosphorus and improved the phosphorus cycle in C.oleifera plants,thus increasing the phosphorus nutrition of C.oleifera.