Effects Of Funneliformis Mosseae On Cd Uptake And Accumulation Of High And Low Accumulation Capsicum

Guizhou Capsicum ranked first in the planting area,processing scale and market distribution,and so on.However,the background value of soil cadmium（Cd）in Guizhou was much higher than that in other regions of the country.Excessive soil Cd not only affected the growth and development of Capsicum but also endangered the health of consumers.To some extent,it limited the sustainable development of the Capsicum industry in this region.Funneliformis mosseae（Fm）was a kind of plant symbiotic fungi widely distributed in soil,which had no specificity to the host.The preliminary experiment showed that the ability of inoculation Fm to promote Cd fixation in Capsicum roots was better than that of other strains.Therefore,this study explored the effects of inoculation Fm on the absorption and accumulation of Cd in high and low accumulation Capsicum,the Cd fixation in roots,and the secretion of Capsicum roots through soil pot experiments and sand culture experiments.The results are as follows:（1）Under different Cd concentrations,the tested strain Fm could infect―La-yan 101‖with high Cd and―La-yan 201‖with low Cd successfully.The infection rate was higher than60%under each treatment condition,and the infection effect of―La-yan 101‖was better than―La-yan 201‖.Under the non-inoculation condition,the soil Cd content did not change significantly after Fm inoculation with―La-yan 201‖,and the soil Cd content decreased significantly after Fm inoculation with―La-yan 101‖at T2 concentration(The content of Cd was 1.5 mg·kg^-1)by 24.7%.（2）The Cd content in fruits of―La-yan 101‖and―La-yan 201‖decreased 19.1-37.4%、5.02-35.4%,after Fm inoculation under Cd stress.Compared with non-inoculation,Cd content in roots and stems of―La-yan 201‖decreased 23.9%、21.7%significantly at T3concentration(The content of Cd was 3.0 mg·kg^-1),and Cd content in roots of―La-yan 101‖decreased at all concentrations.（3）Non-damage micro measurement experiments showed that the uptake of Cd by roots of two Capsicum was inhibited after inoculation with Fm,and the average flow rate of Cd²⁺in roots of―La-yan 101‖decreased more than that of―La-yan 201‖,while the temporal dynamics of xylem sap showed that the xylem of―La-yan 201‖had stronger ability to transport Cd,indicating that the key factor affecting the accumulation of Cd in the aboveground part of Capsicum was the transport capacity of Cd in the xylem,rather than the absorption capacity of Cd by roots.（4）Inoculation with Fm could not only increase the GRSP content in the soil of the two Capsicum varieties but also change the chemical composition of root exudates of Capsicum.After inoculation,the phenolic content in root exudates of Capsicum increased,which may be the result of the defense mechanism of Capsicum caused by Cd stress.Meanwhile,the results of path analysis showed that Acetamide and Benzoic acid,2-（1-oxopropyl）-had the greatest correlation with Cd content,followed by EE-GRSP.In conclusion,Fm could affect the Cd fixation and root exudates composition of Capsicum,reduce the accumulation of Cd in fruits,and provide a basis for the microbial regulation of Cd-contaminated soil and the realization of safe Capsicum production.