氮素水平对油菜根茎叶氮素输出 及角果中氮素积累的影响

通过测定不同施N条件下油菜各器官的N素含量,研究了油菜后期根、茎枝、叶片等营养器官中N素的 输出和角果中N素的积累。其主要结果如下: (1)根、茎枝、叶片中N素积累量的变化呈先增后减的趋势,一般在 开花期前后达最大值;角果中N素总量随角果的生长逐渐增加。增施N肥明显增加各器官的N素积累量,推迟最 大值出现的时间。(2)根系、茎枝、叶片中的N素向外输出的比例随施N量的增加而下降,分别占其最大值的20% ～35%、35%～65%、55%～70%。(3)角果中的N素有30%左右来自叶片中N素的再利用,受施肥量的变化影响 较小; 35% ～10%来自茎枝的N素的再利用,随施N量的增加而减少;来自根系中N素的再利用不足5%;来自开 花后从土壤中吸收的N素约为30% ～60% ,随施N量的增加而增加。

Effect of nitrogen application on nitrogen translocation in roots,stems and leaves and nitrogen accumulation in pods in rapeseed

By testing the content of N in different amount of N fertilizer application to study the remobilization of N in roots,stem and branches and leaves and the accumulation of N in pods in rapeseed.The main results were:(1) The total amount of N in roots,stem and branches and leaves increased firstly and then decreased,usually reached the maximum value around the flowering stage.The total amount of N in pods increased gradually with the growth of pods.Increasing the amount of N fertilizer could increase the total amount of N and delay the appearance of maximum value in different organs.(2) The ratio of N remobilization decreased with the increase of N fertilizer,accounting for about 20%~35%,35%~65% and 55%~70% of their maximum values respectively.(3) 30% of N in pods was remobilized from leaves,affected slightly by the amount of N fertilizer,about 35%~10% from stem and branches,decreased as the increasing of N fertilizer,less than 5% from roots,30%~60% from soil after the beginning of flower was increased as the increasing of N fertilizer.