油菜在冬季易受冻害,一种是由于结冰融化交替,土壤时涨时缩,掀起根系,使根部外露而受冻。晚播迟栽的小苗,叶小根浅,遇到严重低温时,就易发生这种现象。另一种是常见的叶片受冻,有以下三种情况:(1)叶片僵化。叶片在早晨全部僵化,主要是细胞间隙结冰,呈油绿色,脆而易断,到中午后逐渐变软而复原。常发生于零下3～5℃,如温度再低,或时间延续较久的则叶片因细胞 Rape vulnerable to frost damage in the winter, one is due to the melting ice alternately, the soil up when the contraction, set off the roots, the roots exposed and frozen. Sow late planting late seedlings, leaves small roots shallow, encountered severe low temperature, prone to this phenomenon. The other is a common leaf frozen, the following three conditions: (1) leaves rigid. Leaves all rigid in the morning, mainly interstitial icing, was oil-green, brittle and easily broken, until after noon and gradually softened and restored. Often occurs at minus 3 ~ 5 ℃, such as the temperature is then low, or longer duration of the leaves due to the cells