Studies On The Growth And Physiological And Biochemical Characteristics Of Tissue Culturing Seedlings Of Camptotheca Acuminata Under NaCl Stress

In order to study the mechanism of salt （NaCl） tolerance of tissue culture plants ofCamptotheca acuminate and provide reference for the choice of plants with salt tolerance, thispaper carried out researchs of physiology characteristics of salt tolerance of tissue culture plants attwo stages of tissue culture of Camptotheca acuminate and used methylation sensitive enzymeMsp Ⅰa nd HapⅡcombining ISSR-PCR to analysis change of DNA methylation of tissue cultureplants of Camptotheca acuminate under different stress concentrations of NaCl.The main findings were as follows:（1） The best adventitious bud multiplication medium was WPM+BA0.5mg·L^-1，the budmultiplication factor was5.6, and the length of the longest shoot was0.6cm; the optimal rootingculture medium was WPM+BA0.5mg·L^-1, the rooting rate was95%, the length of the maximumroot was4.7cm; the best seedling culture medium was modified WPM+IBA0.1mg·L^-1+ZT0.5mg·L^-1, the maximum increased amount in height was2.5cm, the longest average seedlingdiameter was up to1.15mm.（2） At the adventitious bud multiplication culture of tissue culture plants of Camptothecaacuminate, NaCl concentration of15mmol/L is conducive to the growth of tissue culture plants ofCamptotheca acuminate which manifests as promoting increase of seedling height increment,regeneration index and bud length. At rooting culture of Camptotheca acuminate, NaClconcentration of30mmol/L promotes increase of root number and root length. concentration of120mmol/L restrains the growth of tissue culture plants of Camptotheca acuminate, whichmanifests as inhibiting seedling height increase, reducing regeneration index,shortening budlength,causing drop of rooting rate and decreasing root number and root length.（3） Camptotheca acuminate tissue culture under30mmol/L stress NaCl SOD activity, CATactivity, soluble protein and proline content in Camptotheca acuminate tissue cultureadventitious bud proliferation and rooting period were higher than the control group.（4） NaCl stress made the relative conductivity and MDA content in the leaves of Camptothecaacuminate tissue culture increase significantly, and the content increase rate raised as saltstress intensified. （5） NaCl stress made chlorophyll a, chlorophyll b, carotenoids, chlorophyll a/b and totalchlorophyll content in the leaves of Camptotheca acuminate tissue culture seedling decreasesignificantly. Description of Camptotheca acuminate tissue culture chlorophyll has been acertain degree of damage under NaCl stress.But the variance analysis showed that NaCl30mmol/L treatment, no significant difference from the control group.（6） NaCl90-105mmol/L concentration in leaves of Camptotheca acuminate tissue culturemethylation phenomenon obviously.NaCl30mmol/L stress the methylation degree is smaller,suggesting that the extent of NaCl stress lighter. And the degree of methylation andproliferation of cultured higher rooting culture.（7） Comprehensive analysis shows that, Camptotheca acuminate tissue under30mmol/L stress inNaCl can better growth, and Camptotheca acuminata seedlings can resistance to NaCl30mmol/Lstress.