小麦幼穗分化的温光反应研究──Ⅱ：光周期反应对小麦穗分化的影响

光周期控制试验结果表明，小麦各穗分化期均受到光照长度的控制，在全期短日照条件下，二棱期、护颖期、雌雄蕊分化期的出现受到强烈的抑制．在前期长日照的基础上，不同时间转入短日照后．随时间后延，短日抑制效应减弱．雌雄蕊期由长日转入短日时，依品种、温度及前期长日照的日照长度不同，穗分化进程所受抑制程度有差别，光周期不敏感品种在较高温度条件下，基本不受影响．小麦幼穗分化对光周期变化的反应具有＇滞后＂现象．本文认为，随品种、温度及日照长度的不同，小麦对光周期反应的要求可能在二棱－抽穗的任一时期内完成．不宜用某一特定的穗分化期来标志光照阶段的开始与结束．

STUDY ON THE RESPONSE OF WHEAT SPIKE DIFFERENTIATION TO TEMPERATURE AND DAYLENGTH 2 EFFECT OF PHOTOPERIOD

By experiments under controlled daylcngth,it was showed that the whole spike differentiation process,including doublc-ridge,differentiation of glume,stamen and pistil,as well as heading,was prohibited under 8h daylength.When the plants were transfered from long to short daylength,the prohibiting effect reduced as the transfering dates delayed and it was related to the wheat varieties,temperatures and the length of long daylength.When transfered at stamer-pistil differentiation stage under high temperature,the non-photosensitive cultivars did not show response to following short daylength.The response of spike differentiation to varying daylength had a characteristic of“lag response”,It is suggested that,depanding on cultivars,temperature and length of daylength,the reqirement of wheat for photoperiod could be satisfied at any stage from double-stage to heading.The beginning or finishing of photophase should not be marked by a certain differentiaton stage in general.