Study On Comparison Of Salt-Resistance Abilities Among Different Populus Tomentosa Clones And Gene Transformation For Salt Tolerance

In this study, the eight clones of Populus tomentosa were used for evaluating their salt-resistance abilities through the experiments. Under the condition of salt stress, the survival performance, stress appearance and height growth rates of clones were investigated; at the same time, chlorophyll content, proline content and MDA content were measured. Furthermore, the mtlD gene was transformed into the plantlet of Populus tomentosa successfully. The results were as follows:1. Under the condition of salt stress, it was all difference among 8 clones indicated by the survival performance, stress appearance and height growth rates.2. With the increase of salt concentration, the chlorophyll content decreased; The proline content fluctuated and the MDA content climbed gradually.3. According to growth performance of eight clones affiliated with their physiological and biochemical parameters, the salt resistance abilities of clones were judged three types: L5 and L16 had a good tolerance to salt stress; the abilities of LI 1, L14 and L27 to salt resistance were moderate; LI2, L13 and L24 were the most sensitive to salt stress.4. The optimum regeneration system of Populus tomentosa was founded as follows: proliferation medium was MS+ 6-BA 0.5mg/L+NAA0.1mg/L+sugar 30g/L+agar 4.5g/L; regeneration medium of leaf-explant was MS+6-BA 3.0mg/L+NAA0.1mg/L+ sugar30g/L+agar 4.5g/L; rooting medium was MS+NAA0.3mg/L+sugar 20g/L+agar 4.5g/L.5. The test demonstrated the best leaves for adventitious bud regeneration stem from rooted plant. And, there were significant effects on adventitious bud regeneration by the way of adding different concentrations of AgNO3. At the same time, the effects ofIdifferent types of media on the regeneration of adventitious shoots were studied, indicating that there was no difference in adventitious shoot induction. 6. The optimized condition for transformation of Populus tomentosa was co-cultured with an engineered A.tumefaciens strain carrying mtlD gene from E. coli. for 2-3days and infected with A.tumefaciens concentration of OD6oo=0.3-0.5 about 10-20min. The buds were screened in the differentiation culture media containing Km 50mg/L. At last, the integration of the mtlD gene into plant genomes of transgenic P. tomentosa was confirmed by PCR-Southern hybridization and PCR analysis.