Effects of exogenous salicylic acid on physiological traits and CBF gene expression in peach floral organs under freezing stress

To elucidate the effects of exogenous salicylic acid (SA) treatment on the cold resistance of peach flower, the floral organs of two peach cultivars were treated with 20 mg/L SA and stored at 0 degrees C for observation and sample collection. Water application was the control. After a treatment period, the anther relative water content of the control and SA-treated flowers decreased. The extent of the reduction was greater in the control, suggesting that the SA treatment significantly helped to maintain the anther water content of peach. Analysis of the stigma relative electric conductivity revealed that the SA treatment prevented membrane injury during the low temperature treatment. Additionally, we measured CBF gene expression at low temperature in the petal, stigma and ovary. The expression was markedly upregulated in the cold-treated floral organs. CBF gene expression after SA treatment was higher than in the control when cold conditions continued. These results suggest that the effects of SA on ameliorating the freezing injury to peach floral organs and on enhancing cold tolerance may be associated with the induction of CBF gene.