本文应用珠江三角洲(20°30′～23°10′N)当前推广的早、晚稻29个品种,在自然和人工控制共12级光长处理下进行研究,结果表明:从早、晚稻光周期反应,区分出了早稻属于中性类型。晚稻属于短日性类型。品种出穗日数,在自然光照下,随早、中、迟熟品种而递次增多,随早,中,晚季而递次减少,表现出连续变异性。早稻感光性弱,短日高温生育期中至长,感温性弱至中。晚稻感光性强,短日高温生育期短至中,感温性强至中。光温反应型可分8个型,早稻包括4个型,晚稻有4个型。晚稻有数品种在15小时光照处理下不出穗,24小时连续光照下又出穗。用电子显微镜观察两者的顶叶叶片组织结构,见到前者叶绿体内片层排列紧密,淀粉较小,后者叶绿体内的片层排列疏开,淀粉粒较大,或数量较多。但怎样影响出穗期还待进一步研究。品种出穗期和各个生育阶段的有效积温,采用日平均温度减去水稻生育的下限和上限温度;以12°～26℃计算有效积温,早稻的在早、中、晚季,晚稻的在晚季都最稳定。暗室夜高温(30.1℃)对早稻出穗日数的影响甚微。 In this paper, 29 varieties of early and late rice popularized in the Pearl River Delta (20 ° 30 ’~ 23 ° 10’N) were studied under natural and artificial control with a total of 12 light treatments. The results showed that from the early and late rice photoperiod The reaction distinguishes that early rice is of neutral type. Late rice is a short type. Under natural light, the earliest heading date of varieties increased successively with the varieties of early maturity, middle maturity and late maturity, and decreased continuously with the early, middle and late seasons, showing continuous variability. Sensitive to weak early rice, short-term high-temperature growth period to long, warm temperature weak to medium. Late rice sensitive, short-term high temperature growth period short to medium temperature strong to. Photo-thermal response can be divided into 8 types, including 4 types of early rice, 4 types of late rice. Several varieties of late rice in the 15-hour light treatment no spike, 24 hours of continuous light and spike. The structure of the parietal lobe was observed by electron microscopy. The former showed that the lamellae of chloroplast in the former were closely arranged and the starch was smaller, while the lamellae of the latter chloroplast were arranged in a wide range, with larger starch grains or larger numbers. However, how to affect the heading stage needs further study. The heading date and the effective accumulated temperature in each growth stage of the cultivars were calculated by subtracting the lower limit and the upper limit of rice growth from the average daily temperature. The effective accumulated temperature was calculated from 12 ° C to 26 ° C. Seasons are the most stable. Night dark night temperature (30.1 ℃) had little effect on the heading date of early rice.