冬小麦抗逆栽培技术原理的研究 Ⅲ.中后期重施氮肥对小麦灌浆过程的影响

在小麦生育前期施用氮肥不过量和苗株稳健生长的情况下,通过孕穗期重施氮肥,观察研究结实灌浆过程中植株各部位干物质积累的变化,得知中后期施用氮肥可增强叶片素质,提高后期光合效率、延长灌浆时间、千粒重明显增加.同时,茎、叶鞘也相应得到充实,使小麦后期的抗倒、抗“干热风”能力增强,并且从籽粒灌浆速度变化和千粒重增重过程看出,中后期追施氮肥即使过量,也没有出现贪青现象.

STUDIES ON THE PRINCIPLES OF STRESS RESISTANCE TECHNIQUES OF WINTER WHEAT CULTIVATION III. The Effect of Heavy Application of N-fertilizer on the Process of the Grain Filling in the Middle and Late Growth Stages.

The study was made about the effects of heavy application of N-fertilizer in the booting stage on the process of grain filling and the changes of dry matter production in the various organs of winter wheat plant in steady growth under no excessive N-fertilizer application .Results indicated:l.The application of N-fertilizer in booting stage can increase the weight of leaf per unit area, the strength of grain filling, 1000 grain weight and also extend the filling time.2. With the heavy N-fertilizer application in booting stage, vegetable organs e.g. the leaf, sheath and stem etc. Became strong, with the rate of grain filling speeded up. Because of this, the ability of lodging resistance, draught resistance and draught-heat resistance could be strenghthen. The dry matter weight of the vegetable organs per unit length or area was heavier under the treatment of N-fertilizer application in booting stage than in the heading stage except the control.3.There was no phenomenon of late maturing which is charac-teristie of reduction of 1000 grain weight with moderate application of N-fertilizer and steady growth of plants. It indicated that there was selective and limited absorption for N-fertilizer in late stage of wheat plants.It was concluded that the main cause for lodging and late maturing at the late growing stage was the extreme application of N-fertilizer and overgoing of N-metabolism in the early stage.