Nitrogen incorporation and remobilization in different shoot components of field-grown winter oilseed rape (Brassica napus L) as affected by rate of nitrogen application and irrigation
Nitrogen incorporation and remobilization in different shoot components of field-grown winter oilseed rape (Brassica napus L) as affected by rate of nitrogen application and irrigation
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DOI：
10.1007/bf00010132
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发表时间：
1995-12-01
期刊：
影响因子：
4.9
通讯作者：
Mogensen, VO
中科院分区：
文献类型：
--
作者：
Schjoerring, JK;Bock, JGH;Mogensen, VO
在田间条件下，包括三种N-15标记施氮量（0、100或200 kg N ha(-1)）和两种灌溉处理（雨养或缺水20 mm浇水）的田间条件下，研究了冬季油菜（Brassica napus L.）不同地上部成分氮吸收、掺入和再利用的季节过程。灌溉水总量为260毫米，从开花前1周到开花后4周，7周内分13次。施氮和灌溉促进了植物生长和氮积累。无论施氮和灌溉处理如何，在开花开始时，茎中存在总芽氮的 50% 以上。开花末期，荚果壁是主要的氮储存，含有约 30-40% 的枝条氮。在所有处理中，从茎和荚果壁再利用的氮量总计约为开花中期这些器官中存在的氮量的 70%。收获时，茎壁和豆荚壁各含有约 10% 的芽总氮，其余 80% 被掺入种子中。种子氮积累对施氮和灌溉响应的主要成分是腋生总状花序的荚果。高达20 kg N ha(-1)，相当于最终芽氮含量的约10%，通过落叶从植物中损失。灌溉使收获时施用的氮的回收率从30%增加到约50%，而施氮水平并不影响氮的回收。 N-15 标记（肥料来源）氮在老叶中所占的氮含量比例高于幼叶，并且前者随年龄增加而增加，但后者则不然。相对于土壤氮，肥料中的氮对营养体氮含量的贡献也大于生殖枝成分的氮含量。开花后地上部氮含量的微小净变化反映了氮输入和输出之间的平衡，导致 N-15 标记的氮与未标记的氮的持续稀释。
The seasonal course of nitrogen uptake, incorporation and remobilization in different shoot components of winter oilseed rape (Brassica napus L.) was studied under field conditions including three rates of N-15 labelled nitrogen application (0, 100 or 200 kg N ha(-1)) and two irrigation treatments (rainfed or watered at a deficit of 20 mm). The total amount of irrigation water applied was 260 mm, split over 13 occasions in a 7-week-period ranging from 1 week before onset of flowering until 4 weeks after flowering.Nitrogen application and irrigation increased plant growth and nitrogen accumulation. Irrespective of N and irrigation treatment more than 50% of total shoot N was present in the stem when flowering started. At the end of flowering, pod walls were the main N store containing about 30-40% of shoot N. The quantities of N remobilized from stems and pod walls amounted in all treatments to about 70% of the N present in these organs at mid-flowering. At harvest, stem and pod walls each contained about 10% of total shoot N, the remaining 80% being incorporated into seeds. The main component contributing to the response of seed N accumulation to nitrogen application and irrigation was pods in axillary racemes. Up to 20 kg N ha(-1), corresponding to about 10% of final shoot N content, was lost from the plants by leaf drop.Irrigation increased the recovery at harvest of applied N from 30% to about 50%, while the level of N application did not affect the N recovery. N-15 labelled (fertilizer derived) nitrogen constituted a greater proportion of the N content in old leaves than in young leaves and increased with age in the former, but not in the latter. Relative to soil N, fertilizer derived N also contributed more to the N content of vegetative than to that of reproductive shoot components. Small net changes in shoot N content after flowering reflected a balance between N import and export, leading to continuous dilution of N-15 labelled N with unlabelled N.