Influenceof Ectomycorrhizal Fungi On Thelead Tolerance Of Female Andmale Cuttings Of Populus Cathayana

Heavy metal pollution in soil has been focused in the world,because of its inhibitory effect on plant growth and safety problem on agriculture product.At present,phytoremediation is the most prospected strategy to improve soil heavy metal contamination due to the lower cost,the easier operation and the less influence to the environment.Mycorrhizal fungi in the joint repair technology of plant-microbe has become hot topic the research.Inthisstudy,ectomycorrhizal fungi(Leucoagaricus sp.)was introduced to investigateits that effects on sex-specific responses of Populus cathayana,which in morphology,physiology,and phytoremediation capacity of Pb,when exposed to a diffused level of Pb pollution,which was to indicate improve the tolerance of plant against heavy metals by ECMF and provide the basis onalleviating Pbtoxicity in agricultural production.The main results and conclusions were asfollows:1.With the increase of Pb concentration,the biomass of males was increased and then decreased,however,the biomass of females was significantly decreased.It suggested that males have a better ability for adapting to theenvironment than females under lower Pb stress.Inoculation with fungi can improve the biomass of P.cathanaya.2.The photosynthetic rate,transpiration rate,stomatalconductance of P.cathayana in both sexes in leaves were declined under higher of Pb stress.Fungal inoculation had a positive effect on photosynthetic rate,transpiration rate,stomatal conductance under Pb stress,and decrease the leaves rooms carbon dioxide concentrations.It suggested that ECMF can adjust the photosynthetic rate,whichinfluence totranspiration rate and stomatalconductance,thus alleviating the negative effects of Pb stress on hostplants photosynthesis.3.With the increase of Pb concentration,chlorophyIIa and chlorophyII b content were significantly decreased in the both sexes.Fungalinoculation had no effect on the value of chlorophy II a/b,but exposure to Pb alone was improved the value of chlorophyII a/b.4.With the increase of Pb concentration,the MDA content of leaves was significantly improved in both sexes,the MDA content in females was considerably higher than males.When was fungi inoculated,the MDA content of leaves was declined in both sexes than non-mycorrhizal cuttings,especially in females.5.With the increase of Pb concentration,SOD activity increased and then decreased on females of leaves.However,SOD activity had no effect on males under lower of Pb stress.CAT activity of P.cathanaya had the similar change trend with SOD activity.Fungal inoculation can improve the activity of SOD,CAT and APX of P.cathanaya in leaves.6.With the increase of Pb concentration,the content of proline and souble suger were significantly increased.When was fungi inoculated,the content of proline and souble suger of leaves were increased in both sexes than non-mycorrhizal cuttings,proline and souble suger,indicator of an osmolyte forplant osmotic adjustment,thus decrease the damage of membrane.