Effects of heat shock treatment on total phenol content and PAL, PPO, POD activities in Diospyros vaki explants

The explants of Diospyros vaki is easy to occur browning during tissue culture process.In order to prevent browning,explants should be treated by heat shock before cultivation.Phenols content and activities of PAL,PPO and POD in D.vaki c.v.‘Baohuatianshi' leaves were researched,and physiological mechanism of heat shock treatment preventing browning was discussed.The results showed that browning degree of leaves was decreased significantly after heat shock treating,and total phenol content and activities of PAL and PPO were also lower than the control.But preventing effect of hot shock treatment on POD activity was not obvious.It suggested that heat shock treatment could inhibit synthesis and oxidation of phenols,and decreased quinones content,which was browning production,through reducing activities of PAL and PPO in explants.So heat shock treatment could effectively prevent browning.