盐胁迫对长春花幼苗生长和生物碱含量的影响

以NaCl浓度分别为0、50、100、150、200和250 mmol·L^-1的1/2 Hoagland营养液处理长春花幼苗，7 d后测定其鲜质量、干质量、丙二醛(MDA)和叶绿素含量、色氨酸脱羧酶（TDC）和过氧化物酶（POD）活性等生理指标及文多灵、长春质碱、长春新碱和长春碱等生物碱含量.结果表明：NaCl显著地降低长春花幼苗的鲜质量和干质量，提高MDA含量；叶绿素含量在低盐浓度(50 mmol·L^-1)下与对照相比差异不显著，在高于50 mmol·L^-1时随NaCl浓度的增加而逐渐降低；在NaCl处理下，POD活性与对照相比显著上升；TDC活性在50 mmol·L^-1 NaCl处理下活性最高，而后随盐浓度的增加逐渐降低；文多灵、长春质碱、长春新碱和长春碱含量都是在50 mmol·L^-1NaCl处理下最高，分别为4.61、3.56、1.19和2.95 mg·g^-1，并显著高于对照及其他处理.盐胁迫虽然在一定程度上抑制了长春花幼苗生长，但促进了其生物碱的代谢，提高了生物碱含量；50 mmol·L^-1NaCl处理对长春花吲哚生物碱代谢的促进作用最大.

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

Catharanthus roseus seedlings were grown in 1/2 Hoagland solution containing 0250 mmol·L^-1of 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·L^-1, but decreased with increasing NaCl concentration when the NaCl concentration was above 50 mmol·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·L^-1, but decreased with increasing NaCl concentration. The vindoline, catharanthine, vincristine, and vinblastine contents were the highest under 50 mmol·L^-1NaCl stress, with the values being 4.61, 3.56, 1.19, and 2.95 mg·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·L^-1 of NaCl had the greatest promotion effect on the alkaloid content of C. roseus eedlings.