[Effects of NaCl on the growth and alkaloid content of Catharanthus roseus seedlings].

Catharanthus roseus seedlings were grown in 1/2 Hoagland solution containing 0-250 mmol x L(-1) of NaCl, and their fresh and dry mass, malondialdehyde (MDA) and chlorophyll contents, tryptophan decarboxylase (TDC) and peroxidase (POD) activities, and vindoline, catharanthine, vincristine and vinblastine contents were measured after 7 days. The results showed that NaCl markedly decreased the fresh and dry mass but increased the MDA content. The chlorophyll content had no difference with the control when the concentration of NaCl was 50 mmol x L(-1), but decreased with increasing NaCl concentration when the NaCl concentration was above 50 mmol x L(-1). There was a significant enhancement of POD activity under NaCl stress. The TDC activity was the highest when the concentration of NaCl was 50 mmol x L(-1), but decreased with increasing NaCl concentration. The vindoline, catharanthine, vincristine, and vinblastine contents were the highest under 50 mmol x L(-1) NaCl stress, with the values being 4.61, 3.56, 1.19, and 2.95 mg x g(-1), respectively, and significant higher than the control and other treatments. Salt stress could restrain the growth of C. roseus seedlings, but promote the metabolism of alkaloid and increase the alkaloid content. 50 mmol x L(-1) of NaCl had the greatest promotion effect on the alkaloid content of C. roseus seedlings.