摘要
两年的试验结果表明,深色晾烟采收晾制后,体内硝酸还原酶活性剧烈下降。晾制后3～5d,叶肉和主脉体内硝酸还原酶活性即下降至0。晾制3周内体外硝酸还原酶活性极低,几乎接近0。晾制3周后逐渐增加,两年试验分别在晾制后5—6周达到最高峰,这可能与微生物有关。两种电子供体之间,使用methyl viologen的活性大于使用NADH的,但之间无显著差异。晾制过程中体外硝酸还原酶活性变化规律与亚硝酸和烟草特有亚硝胺变化的规律一致,只是变化时间比后二者提前一周,这个结果表明烟草特有亚硝胺的前体物质亚硝酸盐主要来自体外硝酸还原酶还原的亚硝酸盐。
A two years study indicated that nitrate reductase activity (NRA) in vivo sharply decreased after harvestand was zero after three to five days air-curing both in lamina and midrib. NRA in vitro was very low,and was near zero in 3 weeks during air-curing both in lamina and midrib and increased after 3 weeks air-curing and reached maximum after 5 weeks to 6 weeks air-curing in midrib. This observation suggests the presence of microbes on the leaf surface contributing to NRA. Two electron donors was not significant, methyl viologen was slighter higher than with NADH. Changes of NRA in vitro was the same nitrite and tobacco-specific nitrosamines (TSNA) ,and changes of NRA was faster than that of nitrite and TSNA. This results showed that nitrite ,the precursor was from NRA in vitro.
出处
《西南农业学报》
CSCD
2004年第B05期263-266,共4页
Southwest China Journal of Agricultural Sciences
关键词
硝酸还原酶
烟草
晾制
亚硝酸盐
烟草特有亚硝胺
dark tobacco
air-curing
nitrate reductase activity
changes
nitrite
tobacco-specific nitrosamines
