Effects of exogenous abscisic acid on cell membrane and endogenous hormones contents in leaves of sugarcane seedling under cold stress

To explore the effect of spraying ABA treatment on the cold resistance of sugarcane,the changes of cell membrane permeability and the levels of endogenous hormones in leaves of sugarcane seedling were studied under cold stress and ABA treatment using two sugarcane cultivars GT28 with strong cold resistance and YL6 with weak cold resistance.The plants were sprayed with ABA before 12 h of cold treatment and leaf samples were taken at different time of cold treatment.The result showed that the cell membrane was injured.GA3 decreased while the relative electrical conductance,the contents of MDA,ABA and the ratios of ABA/GA3,ABA/IAA and ABA/ZR were increased under the cold stress.After spraying ABA,the injury of cell membrane was effectively alleviated,the contents of MDA and GA3 were decreased but the contents of proline and ABA and the ratio of ABA/GA3 were increased,reflecting the improvement of cold resistance of sugarcane seedlings.It is concluded that the important physiological bases could be characterized with lower contents of MDA and GA3,higher contents of proline and ABA,and higher ratio of ABA/GA3 in leaves of sugarcane seedling.