Effects Of Exogenous Calcium And Ectomycorrhizal Fungi On Drought Tolerance And Rhizosphere Microecology Of Pinus Sylvestris Var.Mongolica

In this study,1-year-old Pinus sylvestris var.mongolica seedlings were inoculated with ectomycorrhizal fungi and treated with exogenous Ca²⁺under drought and non-drought stress.The growth index,antioxidant enzyme activity,content of related plant hormones,content of osmoregulation substances and microecological index of rhizosphere soil were analyzed and tested.The purpose was to explore the effects of exogenous calcium and ectomycorrhizal fungi on drought tolerance and Rhizosphere microecology of P.sylvestris var.mongolica,in order to provide new practical ideas for adversity afforestation and ecological environment construction in arid areas of western Liaoning Province.The main results are as follows:（1）The inoculation of ectomycorrhizal fungi expanded the tip of the root tip of P.sylvestris var.mongolica,and the application of exogenous Ca²⁺promoted the higher number and infection rate of mycorrhizal,the formation of mycorrhizal thick and obvious bifurcated branches,and the growth of seedlings was generally higher than that of the non inoculated treatment group;（2）Under drought stress,the activities of catalase,peroxidase,superoxide dismutase and ascorbic acid peroxidase in P.sylvestris var.mongolica seedlings inoculated with ectomycorrhizal fungi and applied with exogenous Ca²⁺were higher than those in non-inoculated P.sylvestris var.mongolica seedlings,and all reached a very significant difference level（P<0.0001）;（3）Under drought stress,the contents of malondialdehyde and free proline in all treatment groups inoculated with ectomycorrhizal fungi and applied with exogenous Ca²⁺were lower than those in CK,and the content of malondialdehyde in Ca+E treatment group was the lowest,which was significantly different from CK（P<0.0001）;（4）Under drought stress,the levels of zeatin,gibberellin and auxin in seedlings were significantly higher than CK（P<0.0001）.Compared with other treatment groups,Ca+E treatment showed the lowest level of abscisic acid;（5）After inoculation of ectomycorrhizal fungi and application of exogenous Ca²⁺,the change trends of soil enzyme activity and soil microbial content in the rhizosphere of P.sylvestris var.mongolica seedlings were relatively consistent,which were improved in varying degrees,and the enzyme activity of Ca+E treatment group was the highest,which was significantly different from CK（P<0.0001）.To sum up:after inoculating ectomycorrhizal fungi and applying exogenous Ca²⁺,mycorrhizal seedlings and non-mycorrhizal seedlings are very different in growth and stress resistance.Ectomycorrhizal fungi and exogenous Ca²⁺can protect P.sylvestris var.mongolica seedlings from environmental stress and effectively improve rhizosphere microecology.And ectomycorrhizal fungi and exogenous Ca²⁺were applied to P.sylvestris var.mongolica at the same time,which played a"synergistic"effect,that is,"1+1>2".