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一九七七年,武威春小麦结实小穗数普遍下降,每穗粒数减少,群众反映“结头空”。我们调查27个样点,平均结实小穗数较一九七六年减少2.5个;调查18个样点,平均每穗粒数较一九七六年减少11粒。这样普遍、大幅度地下降,原因是什么?我们从这一年的农业气象条件方面作了分析。结实小穗数的形成主要是在拔节——抽穗期间,一般在5月下旬至6月上旬,这时期是小穗分化——四分体分化完成阶段,是对外界条件尤其是对温度最敏感的时期。遇到低温,雄花受害,严重时雌花同样受害;这一时期热量条件不足,小麦的小花分化、雌雄蕊分化、药隔期和四分体分化都不能很好完成,造成个体发育不良,使结实小穗数减少。一九七七年5月下旬至6月上旬≥度活动积温只有324.8度,是解放以来热量最少的一
In 1977, the number of strong spikelets of Wuwei spring wheat generally dropped, and the number of grains per panicle decreased. The masses reflected “knot empty”. We surveyed 27 sample points with a decrease in the average number of spikelets from 2.5 in 1976 as compared with that in 1976. A total of 18 sample sites were surveyed, with an average of 11 fewer grains per spike than in 1976. What is the reason for such a general and substantial drop? We have analyzed this year’s agrometeorological conditions. The formation of strong spikelet is mainly in the jointing - heading, usually in late May to early June, this period is the spikelet differentiation - tetrad differentiation stage, is the external conditions, especially the most sensitive to temperature Period. Encounter low temperature, male flowers suffer, the same time, the female victims of the same period; lack of heat during this period, floret differentiation, pistil and stamen differentiation, drug interval and tetrad differentiation can not be well done, resulting in poor development of individuals, so strong Spikelets decreased. From late May to early June 2007, the accumulated accumulated temperature of only 324.8 degrees Celsius was one of the fewest calories since liberation