Analytical Research On Salt Tolerance Of Four Guangxi Varieties Of Morus Alba To Salt Stress

In this study, four varieties of Mulberry (Morus alba) from Guangxi province were tested to study their response to salt stress. The difference of seed germination under salt stress between four varieties was measured. In order to comprehensive evaluate the salt tolerance of mulberry, several morphological, physiological, and biochemical indexes were observed. These indexes including seedling rate, plant height, leaf area, proline content, electrolytic leakage rate, POD and CAT activities, MDA content, as well as chloroplyll content. In addition, in order to detect the damage of mulberry caused by salt stress, DNA damage of sensitive mulberry leaf were detected by RAPD marker technology. And the expression of NHX1genes in the root, stem, and leaf of sensitive mulberry were studied though quantitative real-time PCR. The major conclusions are as followed:1. Under NaCl salt stress inhibited the germination energy, germination percentage, germination index, root length, seedling length, activity index and water content, with increasing salt concentration, these index showed a downward trend in varying degrees. Gui12#> Gui62#> You2#> Youl#was assessed by the comprehensive membership function calculation.2. In NaCl salt stress, the seedling rate, plant height, and leaf area of mulberry increased. Both the POD and CAT activity were decreasing after treated with0.15%NaCl. The proline content, electrolytic leakage rate, MDA content, and chloroplyll content were increasing in the salt condition. In addition, these indexes were calculated by membership function, the salt tolerance of mulberry was as follows:Guil2#> Gui62#> You2#> Youl#.3. After mulberry treated by salt, the value of FO and Y(NO) increased, and Fm remained the same basically, and the values of Fv/Fm, Y(II) as well as ETR decreased. In addition, the changing trend of NPQ was different between mulberry varieties.4. DNA damage of mulberry leaf was detected by RAPD marker technology. Both RAPD marker technology and dendrogram showed that NaCl concentration has positive correlation with DNA damage of mulberry. 5. The expression of NHXl gene were detected by real-time PCR, the results showed that the expression of NHX1was increased in root, stem and leaf after treated by NaCl.