to clarify the underlying physiological mechanism of gibberellic acid (ga) in cold tolerance, the effects of exogenous ga3 on malondialdehyde (mda), osmoregulation substances and endogenous hormones levels in the tiller nodes of two wheat cultivars, namely, dongnongdongmai 1 (a cold insensitive cultivar) and jimai 22 (a cold sensitive cultivar), were investigated at three periods of cold winter...