硝普钠对NaCl胁迫下长春花幼苗光合及生物碱的影响

在温室沙培条件下,研究了不同浓度外源NO供体硝普钠(SNP)对50 mmol L-1NaCl胁迫下长春花幼苗生长、光合特性和生物碱的影响。结果表明:(1)在用0.05～2.0 mmol L-1 SNP缓解50 mmol L-1NaCl胁迫中,0.1mmol L-1 SNP缓解效果最好,长春花幼苗的鲜重、干重、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和过氧化物酶(POD)活性分别较S1(50 mmol L-1NaCl)处理显著增加18.8%、13.9%、20.7%、19.1%、8.5%和32.6%,而细胞间隙CO2浓度(Ci)较S1处理显著降低10.3%。(2)当SNP浓度增加到0.5mmol L-1时,色氨酸脱羧酶(TDC)活性、吲哚总碱、长春碱、长春质碱、长春新碱和文多灵含量均达到最高,分别较S1显著增加33.4%、26.9%、32.3%、27.4%、68.8%和50.2%。综上所述:在50 mmol L-1NaCl胁迫下,0.1 mmol L-1SNP对提高光合作用,促进生长,增加生物量的作用最显著;而0.5 mmol L-1 SNP则对提高TDC活性,促进吲哚总碱和4种主要生物碱合成积累作用最显著。

Effects of SNP on photosynthesis and alkaloid content of Catharanthus roseus seedlings under NaCl stress

A sand culture experiment was conducted in greenhouse to study effects of exogenous nitric oxide donor(SNP) on growth, photosynthetic characteristics and alkaloids contents of Catharanthus roseus seedlings under 50mmolL-1 NaCl stress. Results show: (1) 0.1mmolL-1 SNP was the highest in effect of alleviating the stress caused by 50mmolL-1 NaCl, and significantly increased fresh weight, dry weight, Pn, Gs, Tr and POD activity by 18.8%, 13.9%, 20.7%, 19.1%, 8.5% and 32.6% respectively, but decreased Ci by 10.3% as against Treatment S1 (50mmolL-1 NaCl). (2) In Treatment S4, where the concentration of SNP increased to 0.5mmolL-1, the TDC activity, total indole alkaloids, Vinblastine, Catharanthine, Vincristine and Vindolin contents of the Catharanthus roseus were the highest, compared with Treatment S1, they increased 33.4%, 26.9%, 32.3%, 27.4%, 68.8% and 50.2% respectively. To sum up, 0.1mmolL-1SNP is the best at increasing photosynthesis, promoting growth and raising biomass, however 0.5mmolL-1 SNP is the best at improving synthesis of total indole alkaloids and four main kinds of alkaloids.