Effect of arbuscular mycorrhizal fungi and phosphorus application on the adaptability of Toona ciliata var.pubescens seedlings
The effects of AM fungi and phosphorus on the growth and physiology of Toona ciliata var.pu-bescens seedlings were studied.Using two-factor pot experiment,the seedlings were divided into inoculat-ed(AMF)and non-inoculated(Non-AMF)groups,and treated with different phosphorus concentrations(P0:0 mmol·L-1,P1:1 mmol·L-1,P2:2 mmol·L-1),respectively.The root infection rate,seedling growth,bio-mass,nutrients,chlorophyll fluorescence parameters,soluble proteins,and antioxidant enzymes were measured.The root mycorrhizal infection rate showed that AMF×P1 was higher than AMF×P0 and AM-F×P2,and 220 d seedlings(growth stage Ⅱ)was higher than 120 d seedlings(growth stage Ⅰ).In growth stage Ⅰ,compared to Non-AMF,AMF×P1 and AMF×P2 promoted the plant height,diameter,number of compound leaves,total root length,root surface area,and phosphorus and potassium uptake of seedlings,while AMF×P0 showed no significant change.In growth stage Ⅱ,the growth indicators,biomass,and nitro-gen,phosphorus,and potassium absorption capacity of Non-AMF×P2 were similar to those of AMF×P1 and AMF×P2.Compared to the Non-AMF,inoculation with AM fungi significantly enhanced Fv/F0 and Fv/Fm in the growth stage Ⅰ seedlings,while seedlings of Non-AMF×P0 had the highest F0,and the lowest Fv/F0 and Fv/Fm.In summary,a certain concentration of phosphorus combined with AMF can compensate for the growth inhibition caused by phosphorus deficiency,and the interaction between AMF and phosphorus shows a pro-moting effect on seedling growth earlier than simply applying higher concentrations of phosphorus.