不同形态氮素对甜菜谷氨酰胺合成酶活性的影响

Effect of Different Nitrogen Forms on Glutamate Synthetase Activities in Sugar Beet (Beta Vulgaris L.)

不同施肥水平下利用桶栽研究了硝态氮和铵态氮对甜菜体内氮素同化关键酶 -谷氨酰胺合成酶 (GS)活性的影响 ,并分析了不同处理甜菜块根产量与含糖率的变化 ,初步探讨了氮素营养与甜菜GS活性以及与丰产高糖的关系。结果表明 ,不同形态氮素及其不同施肥水平对甜菜体内的GS活性的影响不同 ,在同一施氮水平上 ,铵态氮处理的GS活性高于硝态氮处理的甜菜GS活性 ,而施用同一形态氮素时 ,GS活性随两种氮素施量的增加而增加 ,根产量也表现相似变化 。

The experiments of NO 3 --N and NH 4 +-N fertilizers on Glutamate Synthetase (GS) activities in root of sugar beet of cultivar Tian Yan-7 were conducted under four kinds of nitrogen levels, ie. 0, 60, 120, 180kg/hm 2 in pot culture in the experimental station of sugar beet physiology during the whole period of growth in 1997. The objectives of this study were to preliminarily understand conditions of performing highly efficient ammonia assimilation pathway and analyze changes of root yield, sugar content under different nitrogen forms. The results showed that different nitrogen forms effects GS activities. It was under NH 4 +-N rather than NO 3 --N that GS activity in root was relatively high. Different nitrogen forms influenced root yield, sugar content. Root yield at harvest increased with increase of nitrogen both under NO 3 --N and NH 4 +-N, however, the values were very unconsistent, and they were bigger under NO 3 --N than under NH 4 +-N. Sugar content declined significantly with the increase of NO 3 --N fertilizer and reached the lowest under N180, and rose with the increase of NH 4 +-N from 0 to 120kg/hm 2.