氨基酸和尿素替代硝态氮对水培不结球白菜和生菜硝酸盐含量的影响

 研究了甘氨酸、异亮氨酸和脯氨酸的不同组合及尿素替代 2 0 %硝态氮对水培不结球白菜和生菜硝酸盐含量和品质的影响。结果表明 ,在采收前 12d替代处理 ,与对照相比 ,以甘氨酸对不结球白菜和生菜硝酸盐含量降低效果最好 ,甘氨酸、异亮氨酸和脯氨酸三者混合氨基酸其次 ,尿素次之 ;同时氨基酸处理也提高了两种蔬菜叶片可溶性糖和蛋白质含量 ,并显著增加了叶片全氮量。氨基酸替代硝态氮后 ,增强了不结球白菜叶片硝酸还原酶活性 ,但削弱生菜叶片硝酸还原酶活性。氨基酸和尿素都降低了不结球白菜和生菜体内硝酸盐含量 ,而且对不结球白菜 ,氨基酸与尿素效果相近 ,但对生菜氨基酸比尿素更有效。氨基酸部分替代硝态氮不但可以显著降低两种蔬菜体内硝酸盐含量 ,而且可以改善品质

Effect of Partial Replacement of Nitrate by Amino Acid and Urea on Nitrate Content of Nonheading Chinese Cabbage and Lettuce in Hydroponics

s: We studied on the effect different mixture of glycine (Gly), isoleucine (Iso), proline (Pro), and urea used as partial (20%) replacing nitrate of solution on nitrate content and quality of nonheading Chinese cabbage and lettuce in hydroponice. Five treatments were done 12 d before harvest. Compared to the control group, Gly had the best effect in reducing nitrate content of both vegetable leaves and petioles; the mixture of Gly, Iso and Pro ranked the second and urea the last. Treatments with amino acid could also increase soluble sugar and protein contents of them and enhance total N in leaves significantly. In contrast amino acid enhanced NRA in nonheading Chinese cabbage, while decreased it slightly in lettuce. The results showed that amino acid and urea could reduced nitrate content of both vegetables, but nonheading Chinese cabbage they had almost the same effect. What's more, amino acid was more effective than urea in lettuce. As a result, it was concluded that partial replacement of nitrate with amino acid not only reduced nitrate content, but also improved the quality of vegetables.