小麦籽粒充实期氮素的吸收和再分配及6－苄氨基嘌呤的调节作用

小麦从开花至成熟，其根、茎和叶中的Ｎ素不断地进行着分配和再分配，主要是向穗子输出。成熟时穗Ｎ含量占植株总Ｎ的８２％。在总Ｎ净输出的同时各营养器官也有相当程度的对当前土壤Ｎ的净吸收。在籽粒充实阶段用ＢＡ处理叶式穗均影响营养器官及穗子的Ｎ素吸收、分配和再分配。

Absorption and Redistribution of Nitrogen During Grain-filling Period of Wheat and Their Regulation by 6-Benzylaminopurine

The absorption and redistributionof N during grain-filling period ofwheat (Triticum aestivum L) in all organs as well as their regulation by 6benzylaminopurine (BA) were reportedin this paper. From anthesis to maturity,rootS, stem and leaves of wheat exported 47%, 43% and 75% of theirtoeal N, respectively. Their contributions to ear N accumulation were 3%,11% and 18%, respectively. The remaining 67% of ear N accumulationcame from N currently abSorbed fromsoil. At maturity, 83% of total plantN was found in the ear (Fig. l; Table2). The resultS of 15N tracer experiments indicated that in all vegetative organs there was a net loss of toeal N anda net gain of N from the soil(Table 3).Treatment of leaves twice with BA (0DAA and 18 DAA ) inhibited the export of total N from roots and leaves,but enhanced their current absorption ofN from soil, noticibly decreased the Ncurrently absorbed from soil in the ear,affected the stem to a lesser extent, andas a result, decreased ear N accumulanon significantly; Treatment of eartwice with BA (0 DAA and 18 DAA )inhibited the toeal N export from roots,stem and leavest and at the same time,enhanced the current N absorption byrootS, stem, leaves and ear from soil,and has lesser effect on the ear N accumulation; BA treatment of leaves or earonce (18 DAA) diminished the total Nexported from roots, stem and leaves,but significantly enhanced the current Nabsorption by these organs and especially ear from soil, finally increased theear N accumulation significantly.Treatment with BA on 20 DAA increased ear N accumulation most significantly (Tables 2-4 ).