甜菜硝酸还原酶活性研究

Studies on Nitrate Beductase Activity in Sugar Beet

试验表明,甜菜幼苗期至叶丛快速生长期,叶片中的NR活性迅速上升至最高水平,以后缓慢下降,到糖分积累期迅速下降到最低水平。外源基质条件下NR活性较内源基质条件下高出10倍至几10倍,在高氮条件下NR活性下降.甜菜具有极高的NO_3^-还原潜力。叶片中还原糖含量和NR活性在整个营养生长期均表现为负相关,蔗糖含量与NR活性在糖分积累期呈显著负相关,含氮率与NR活性在各生育时期均呈正相关。外源基质对NR活性的影响随施氮量提高而下降。

It has been shown from the experiment that nitrate reductase activity(NRA) rised rapidly to reach its peak from seedling stage to the period of crown rapid growth. Then it declined slowly, at last, it dropped sharply to its lowest level in the sugar accumulation period. NRA was ten times or even more in the case of exogenous ground substance as high as that in the case of endogenous ground substance, and it decreased under the condition of high nitrogen. There was supreme nitrate reducting potential in sugarbeet. A negative correlation between content of recoverable sugar and NRA was introduced in the leaves during the whole period of vegetative growth. And there was a significantly negative correlation between sugar content and NRA in the accumulation period of sugar and a positive correlation between percentage of nitrogen content and NRA in each growing stage. The influence of exogenous ground substance affected on NRA increased with the decline of amount of nitrogen applied.