Establishment Of Tissue Culture System And Research On Salt Tolerance Mechanism Of Tamarix Chinensis Lour

Tamarix chinensis Lour. is a species mainly distributed in the area of north China. It is a typical salt plant widely distributed in varying degrees of saline soil including Gobi, gravel, clay, sand and therefore is an ideal material to study the salt tolerance mechanism of woody plants. In this present study, a tissue culture system of T.chinensis was established. The changes in some physiological and biochemical indices of T.chinensis under salt stress were determined. Finally, the ODC gene was cloned from T.chinensis by RT-PCR on the base of comparion between different methods for total RNA isolation. The main research conclusions were showed as follows:1. A tissue culture system of T.chinensis was established. The optimal medium for inducing adventitious buds from stem explants was MS supplemented with 6-BA 0.5mg/L and NAA 0.05mg/L. The rooting medium was 1/2 MS.2. The changes in electrical conductivity, contents of malondialdehyde(MDA), proline(Pro) and polyamines(PAs) as well as activities of arginine decarboxylase(ADC), ornithine decarboxylase(ODC) and polyamine oxidase(PAO) were investigated in order to explore the physiological mechanism of T.chinensis under NaCl stress. The results showed that electrical conductivity and Pro content significantly increased during the whole course of experiment while MDA content increased at the early days and then decreased. Put content declined during the days when contents of Spd and Spm greatly accumulated as well as PAs. ADC activity rised at first and then fallen while activities of ODC and PAO rised all through. Correlation analysis showed that the correlation between ODC activity and PAs content was notable as well as thatbetween PAO and PAs. ADC activity was little correlated with PAs content. The decline of Put content, increase of Spd, Spm content and (Spd+Spm)/Put were considered as the important factors which closely related with salt tolerance of T.chinensis.3. The ODC gene was cloned from T.chinensis by RT-PCR. The fragment length was 638bp and found to contain an open reading frame(ORF) of 221 amino acids which highly homologous with the corresponding sequence of registered ODC gene of other plants. CTAB method was the optimal method for isolation of total RNA from T.chinensis with high yield, high purity and preferable quality.These obtained results and conclusions provides important information not only for the research on salt tolerance in woody plants but also for the genetic improvement of salt resistance in agriculture and forest trees.