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在棉花苗期，出现大幅度降温、下霜、降水天气过程时，３ 天、６ 天棉苗，只要棉株上无水珠存留，在０～－ ０．８℃气温下，持续３ 小时，棉株未见受冻害现象；６ 天的棉苗，气温为－ １．５～－ ２．８℃时，持续２ 小时，仍未见受冻害现象；若棉株上有水珠而结冰层，棉株抗冻性明显减弱，在０．４～－ ０．８℃的气温下，持续２ 小时，子叶受冻害株率为５０％ 。
Cotton seedlings, there have been substantial cooling, frost, precipitation weather process, 3 days, 6 days cotton seedlings, as long as the cotton plants without water retention, at 0 ~ - 0.8 ℃ temperature for 3 hours, Cotton plant has not seen the phenomenon of frost damage; 6-day cotton seedlings, the temperature is - 1.5 ~ - 2.8 ℃, for 2 hours, still not seen the phenomenon of frost damage; , The frost resistance of cotton plants was significantly weakened, and the cotyledon frost damage rate was 50% under the temperature of 0.4 ~ - 0.8 ℃ for 2 hours.