叶片是制造和贮存养分的重要器官。如果冬季没有对柑橘采取防冻保暖措施,开春以后,若受寒潮频繁侵袭,或受温差过大的影响,就会引起早春落叶,从而出现树势衰弱,花而不实,坐果率低等现象。因此,在北缘地区种植柑橘必须采取一些有效的对策措施。1.保护根群橘树根群对外界环境反应 Leaves are vital organs for the manufacture and storage of nutrients. If the winter did not take citrus antifreeze measures, after the spring, if by the frequent invasion of the cold, or affected by the temperature difference is too large, it will cause early spring leaves, resulting in frail, faint, fruit setting rate is low and so on. Therefore, the cultivation of citrus in the northern margin must take some effective countermeasures. 1. Protect the roots of the orange root group on the external environment