Betaine Accumulations, Patial CDNA Cloning And The Transcript Expression Of Its Related Enzymes In Dendranthema Lavandulifolium L. Under NaC1 Stress

Glycinebetaine is a very effective osmopretectant existed in many organisms. In higher plants, glycinebetaine is synthesized by the two-step oxidation of choline: the first step is catalysed by choline monooxygenase(CMO; EC 1.14.15.7) and the second step is catalysed by betaine aldehyde dehydrogenase(BADH; EC 1.2.1.8). Several species of the Compositae family, which is known to be rich in betaine and its enzyme genes resources, were studied to investigate the accumulation of betaine in leaves under NaCl stress. Dendranthema lavandulifolium was identified to be a suitable material to be studied on the genes related to the glycinebetaine biosynthesis. Partial cDNA of CMO gene was cloned in stressed D. lavandulifolium, and the expression pattern of BADH gene under stress was analysized. The main results are summarized as follows:1. Based on a number of references with regard to extraction and determination of glycinebetaine in higher plants as well as lots of experiments, a simpler and quicker method with less cost was obtained. Glycinebetaine in plants was extracted with distilled water for 24h, and then mixed with Reinecke salt. Betaine was detected and determined by UV absorbance at 525nm. The coefficient of variation of each sample was lower than 5% and the rates of the impartial recovery were between 99.86%～101.04%. The improved method was shown to be with high definition and accuracy.2. Determination of betaine contents in 7d-salt-stressed Achillea alpina, Aster tataricus, Dendranthema lavandulifolium and Artemisia annua were performed. The results showed that: with the increase of salt stress, the levels of betaine contents in leaves of all experimented plants increased, especially in D. lavandulifolium, which was as 16.67...