一般落叶果树在平均气温低于15℃,日照短于12小时的时候,便开始准备落叶,进入休眠。在此期间过度的寒冷可引起冻害,但一定的低温又是其通过休眠,进行正常生长、发育必不可缺少的外界条件之一。一、低温的重要作用热带或亚热带果树的芽似乎是春性的,而落叶果树的芽则为冬性的,即前者在年发育周期中,不需要经过低温阶段,后者若缺乏这一条件,将产生下述不良后果。 General deciduous fruit trees in the average temperature below 15 ℃, sunshine shorter than 12 hours, they began to prepare leaves, to sleep. During this period, excessive cold can cause frost damage, but a certain low temperature is one of the necessary external conditions for its normal growth and development through dormancy. First, the important role of low temperature Tropical or subtropical fruit bud appears to be spring, while the deciduous fruit tree buds are winter, that the former in the annual development cycle, do not need to go through the low temperature stage, the latter in the absence of this condition , Will have the following adverse consequences.