摘要
研究结果表明，甜菜植株对氮吸收量与施氮量呈正相关（ｒ＝０．９９６￣）；甜菜生育中前期，７０％以上的氮分配到地上部，促进同化器官的建成；高氮处理，甜菜生育后期地上部氮分配率仍较高，不利于块根增长和糖分积累；甜菜叶片硝酸还原酶活性随生育进程而提高，至７月２５日左右达最大值，而后减弱，说明甜菜对氮的吸收与同化，以生育前中期为主，氮肥应作为基肥或早期追肥施用。本文还探讨了施氮量与根产量、含糖率及有害物质的关系。
The experimental results demonstrated that nitrogen absorption in sugar beet plants waspositively correlation to nitrogen application amount,r=0. 996￣**.At the early and mediumsrage of growth period, more than 70% of N was distributed to tops to promote the growth ofassimilation organs and the production of dry matter. Under the condition of higher level Napplication, the distribution of N to shoots was still high at the latter stage of growth, it wasnot a variable for the root enlargement and sugar accumulation, The activity of nitratered uctase in leaf blades became higher w hen the plants older, the peah was on about July2 5,it indicated that the absorption and assimilation of nitrogen in sugar beet plants were mainlyat the early and medium stage of growth. Nitrogen fertilizer should be used as ba sal dressingor early top dressing. when N application amount was iucreased,the quality of root In thisexperiment, N_120 treatment was the optimum N application amount for the highest sugaryield when nitrogen application was excessely high, sugar yield would be low.
关键词
甜菜
氮代谢
块根品质
产糖量
施肥
氮肥
Nitrogen metabolism of sugarbeet
Nitrate reductase
Root quality
Sugar yield
