Study On Salt Tolerance Of Dendrocalamopsis Oldhami Seedlings And Cluster Analysis Of Bamboo By DNA Barcode

In this paper,the growth status,tissue water content,osmotic adjustment substance content and protective enzyme activity of Dendrocalamus oldhami seedlings were studied.By measuring the changes of growth status and physiological and biochemical indexes of Dendrocalamus oldhami seedlings under NaCl stress,the effect of K~+on relieving damage caused by NaCl stress and the effect of drought treatment on K~+on relieving damage caused by NaCl stress were analyzed Salt-tolerant bamboo species resources in coastal beaches and other areas were obtained through investigation,and 98 bamboo species including 32 salt-tolerant bamboo species were clustered by DNA barcode technology.The following research results are obtained in this paper:(1)The germination method with gauze is better than that with sponge pad.The results showed that the germination time of Dendrocalamus oldhami seeds was shortened from 33 h to 7 h,the time of 95%germination was shortened from 168 h to 36 h,and the rate of moldy decreased from 4.47%to 0.30%.(2)On the 15 th day of NaCl stress,the seedlings of CK and 0.25%groups entered the 3leaf stage and grew vigorously;the 0.50%group basically reached the 2 leaf stage,0.75%of the group entered the 2-leaf stage,and the 1.00%group entered the 2 leaf stage,and the plant grew short and weak.The results showed that the average plant height,root length and fresh weight were decreased;the contents of osmoregulation substances such as soluble sugar,soluble protein,proline and betaine increased(P<0.01),the content of MDA increased,SOD increased first,and decreased under high salt concentration,indicating the protective effect on membrane damage;The activities of pod and PPO were first high and then low,indicating the activation effect of low Na~+concentration,and decreased with the increase of Na~+concentration,indicating that high Na~+concentration had inhibitory effect on enzyme activity.(3)When Na~+and K~+were treated at the same time,the release effect of K~+on Na~+stress was very significant(P<0.01),but the release effect was poor under high Na~+and high K~+concentrations;the contents of osmotic adjustment substances such as soluble sugar,soluble protein and proline increased when Na~+concentration was lower than 0.75%(P<0.01),Under the condition of 1.00%Na~+concentration,the content of MDA decreased(P<0.05);When the concentration was lower than 0.75%,the response of PPO to K~+release was faster than that of POD,while the response of PPO was not significant(P>0.05)under the stress of 1.00%Na~+concentration,POD activity decreased with the increase of K~+concentration(P<0.05).The protective effects of physiological and biochemical indexes were consistent with the growth state of plants.(4)The growth of Dendrocalamus oldhami seedlings treated with Na~+and K~+decreased significantly after 15 days of cultivation and 5 days of drought treatment.Under the same Na~+concentration,with the increase of K~+concentration,the content of soluble sugar,soluble protein,proline and other substances regulating permeation increased first and then decreased;Under the condition of Na~+concentration lower than 0.75%,MDA content showed a downward trend;Under the action of K~+,PPO activity decreased,while POD activity responded,and increased at 1.00%high Na~+concentration(P<0.01).The results indicated that drought treatment weakened the effect of K~+on relieving Nastress.Compared with the20 day stable culture group,the drought treatment shortened the root length,shortened the plant height,yellowed the leaves and reduced the water content of the leaves.The contents of proline,soluble protein,soluble sugar and MDA in 0.50%Na~+and 1.00%Na~+groups increased.PPO activity decreased and POD activity increased(5)ITS2 distinguished and clustered Bamboo Species of different genera,but the amplification rate were low,and it was no significant difference in salt tolerance differentiation;matK was no significant classification effect among genera,but it clustered some salt tolerant bamboo species;psbA trnH,ndhF and rps16 had high amplification efficiency,the amplification of bar code was good,psb A-trnH distinguished the genus of Guadua species.ndhF and rps16 effectively clustered the species of Guadua.