A Study on Effect of Ectomycorrhizae on Promoting Castanea mollissima Resistance to Drought and Its Mechanism

Mycorrhizal biotechnology can raise the resistance to drought of Castanea mollissima seedlings:increase the content of bound water in leaf by 12.08%～57.49%;under the condition of water stress,delay the time of leaf wilting up to 1～1.8 days,advance recovery time from wilting up to 0.2～1.2 days after irrigation,decrease wilting coefficient by 21.95%～58.04%,amplify net photosynthesis rate by 3.84%～230.72%.The study demonstrates that inoculation can change the organic structure:increase the degree of leaf succulence by 0.09%～7.88%,specific leaf area by 2.67%～18.83%.It influences the physiological characters:raise leaf water holding ability and decrease water saturation deficit by 3.54%～29.61%.Degree of leaf succulence,specific leaf area and leaf water holding ability were adopted in the research of mycorrhizae firstly.Additionally,transpiration rate (expressing with stomatal resistance and conductance) of inoculating seedlings is lower than the control group under water stress while it is higher under normal condition.At the same time,inoculation improve the water use efficiency of Castanea mollissima,i.e 7.89%～79.78% under water stress,4.78%～63.89% under normal condition.Free proline content increases rapidly in control group seedlings 50.54%.It does indicate that the control group is deficient of water supply,but the inoculated seedlings still not or little feels water stress.In sum, Boletus edulis,Xerocomus chrysenteron and Cortinarius sublanatus are good ECM fungi of Castanea mollissima.