Study On The Growth,Physiological And Biochemical Responses Of Populus Davidiana × P.Alba Var.pyramidalis Seedlings Inducing By Trichoderma Aspereullm

In order to study the growth,physiological and biochemical responses of the tissue-cultured Populus davidiana × P.alba var.pyramidalis induced by the conidia of Trichoderma aspereulln strains at the contents of 1×103 cfu/cm3·soil,the pot expression were carried out under field conditions.Not only the indexes of the plant growth dynamic,biomass yield,photosynthetic characteristics and defense enzyme activities,but also the differential expression of the four coding defense enzyme genes(PadpCu/ZnSOD,PadpPOD21,PadpPPO1 and PadpPAL3)were analyzed inducing by four kinds strains of T aspereullm ACCC30536(Ta536),ACCC31650(Ta650),ACCC32492(Ta492)and T4.The results are showed as followings:1 The action of growth promotion of the poplar seedlings were found inordinately under the induction of these T.asperellum strains.The heights and basal stems of these poplar seedlings were all superior to that of control(CK)in the 60 days treatments by the four T.asperellum strains,respectively.The growth was displayed the trend of first fast and then slow.The biomasses were increased rapidly in July.Meanwhile,the biomasses of these popular seedlings were significantly enhanced inducing by the four kinds of T.asperellum.Moreover,the results of our study showed that the T.asperellum ACCC 30536 had the best growth promotion action on the growth of these poplar seedlings.2 The contents of chlorophyll in the leaves all increased and the photosynthesis of these poplar seedlings had been improved after the induction by the four kinds of T.asperellum conidia strains.After inducing by different T.asperellum strains,the net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Cond)and the intercellular CO2 concentration(Ci)of the poplar seedling leaves were all increased compared with those of control(CK).At the same time,the maximum net photosynthetic rate(Amax),apparent quantum efficiency(Q)and light saturation point(LSP)of the poplar seedling leaves all exceeded those of CK after T.asperellum induction.In addition,the chlorophyll content and chlorophyll a/b ratio of the poplar seedling leaves were all higher than those of CK after induced by the four kinds of T.asperellum.Our results showed that the T.asperellum ACCC 536 has the best induced effect on Populus.3 The activity of superoxide dismutase(SOD),peroxidase(POD),polyphenoloxidase(PPO)and phenylalanine ammonia-lyase(PAL)in the leaves of these poplar seedlings were increased in the pause of inducing by the four kinds of T.asperellum conidia.However,the time points of the four kinds of defense related enzymes reached to the peak value were different after induced by the four different T.asperellum strains.Meanwhile,the soluble protein content in the leaves of these poplar seedling were also increased after four kinds of T.asperellum strains treatment.The experimental results still showed that the best effect on increase the activity of the four kinds of defense related enzymes and the soluble protein content was bringed about by T.asperellum ACCC30536.4 The differential expression of time and space of the genes coding the four different defense related enzymes responsed to the induction of the T asperellum ACCC30536 was analyzed.Thesse genes coding the four different defense related enzymes are PdapCu/ZnSOD?PdapPOD21?PdapPPO1 and PdapPAL3.The results showed that the four genes are all expressed in the root and the leaf,respectively.Meanwhile,the change trend of gene expression was similar after induced by Ta536.The expression level of the genes including PdapSOD,PdapPOD21,PdapPPO1 and PdapPAL3 in the roots of the poplar seedlings responsed to the induction of the T asperellum during 72 hours most showing a change trend of "first upregulated,then downregulated and upregulated again" compared with CK.On the other hand,the expression of the genes coding the four defense related enzyme in the leaves was displayed a trend of first unchanged or slightly decreased,then continuous up-regulated.And the expression time of the four genes responsed to the induction of Ta536 was fall behind that of this four genes in the roots.In a word,all of the four T.asperellum trains have a good effect on the growth promotion of poplar seedlings.The results of our study would provide material base for the bio-fertilizers developing of Trichoderma Immunity-inducing agent,and offer the theory basis for the application of Trichoderma bio-fertilizer on woody plants.