施用腐植酸对叶菜硝酸盐含量的影响

利用盆栽试验,研究了腐植酸对叶菜硝酸盐积累的影响。结果表明,合理施用腐植酸能降低叶菜类蔬菜硝酸盐含量,增强硝酸还原酶活性和增大硝态氮代谢库。通过试验,确定腐植酸最佳施用浓度为0.3g.L-1,此时,小白菜、生菜和菠菜的硝酸盐含量比对照分别降低64.52%、71.74%、72.39%,叶菜的硝酸还原酶活性达到最大值,小白菜和生菜的硝态氮代谢库达到最大值。而菠菜的硝态氮代谢库却在腐植酸施用浓度为0.4 g.L-1时达到最大,这是由蔬菜品种间存在差异导致。

Effect of humic acid on nitrate accumulation in leaf vegetables

A pot experiment was conducted to study the effect of humic acid on nitrate accumulation in leaf vegetables in the experiment.The result indicated that applying humic acid properly decreased nitrate con-centration but increased nitrate reductase activity(NRA) and enlarged nitrate metabolic pool size in leaf vegetables.The result also showed that the best application rate of humic acid was 0.3 g·L-1,at which the nitrate concentrations reduced by 64.52%,71.74% and 72.39%,respectively compared to control and the nitrate reductase activity(NRA) reached the highest values in cabbage,lettuce and spinach,the nitrate metabolic pool size(NMPS) increased to the highest in cabbage and lettuce,while nitrate metabolic pool size(NMPS) in spinach reached the highest point when humic acid was applied at the concentration of 0.4 g·L-1,which was believed to be mainly caused by the difference among types of leaf vegetables.