蔬菜硝酸盐的还原转化特性研究

利用液体培养试验和15N示踪技术 ,研究了通过改变菜心氮源供应条件 ,降低硝态氮累积过程中硝态氮的还原特性。结果表明 ,营养液中的硝态氮源被其他形态氮源替代后能明显降低菜心的硝态氮含量 ;已累积在菜心体中的硝态氮与改变氮源供应条件后新吸收的硝态氮相比较 ,前者的还原率较小 ,较后者难以被还原。改变氮源供应条件前后累积的硝态氮在菜心各部位的分布上存在差异 ,新吸收的硝态氮易累积在代谢活动较为旺盛的部位。尽管在 2种氮源条件下对新吸收硝态氮的还原率相近 ,但供应硝铵态氮源时原累积硝态氮的还原率较仅供硝态氮源时大。

Study on the nitrate reduction characteristic of vegetables

Solution culture experiment and ¹⁵N tracer technology was used to study nitrate reduction characteristic of false pakchoi (Brassica parachinensis) after changing nitrogen source supplying conditions in order to reduce nitrate accumulation. The results showed that nitrate concentration of false pakchoi was significantly reduced when NO₃^--N source in nutrition solution was replaced by other nitrogen source. Compared to the new absorbed NO₃^--N after changing nitrogen source, primary accumulated NO₃^--N reduction percentage was lower and not easier to reduce. There was difference in distribution of different parts of plant between accumulated NO₃^--N before and after changing nitrogen source, new absorbed nitrate was mainly accumulated in parts which metabolism was more vigorous. Although reduction percentage of new absorbed NO₃^--N was similar, primary accumulated NO₃^--N reduction percentage with NO₃^--N and NH₄⁺-N source supplied was larger than that of only NO₃^--N supplied.