Abstract:

This study aims to investigate the physiological response mechanism of A. lucorum adults to low temperature by clarifying the survival, the supercooling point (SCP) and freezing point (FP), as well as the main cold hardiness substances under low temperature. The survival rate of A. lucorum adults was measured by different low temperature treatments. Thermocouple method was used to determine the SCP and FP under different temperature and time. The content of sorbitol, glucose, trehalose and fructose were compared by physiological and biochemical assay. The results showed that after being treated at -5℃ and -10℃ for 24 h or more, the survival rate of A. lucorum adults was 0. After treatment at 0, 5 and 15℃ for 24 h or more, the survival rate was above 96%. After different temperature treatments at 0, 5 and 15℃ for 24 h, the SCP and FP of the adult were decreased. When treated at 5℃ for 24 hours, there was the largest decline. However, when the treatment time extended to 48 h and 96 h, the SCP and FP of the adult were no longer decline. The content of biochemical substances in A. lucorum changed at low temperature. After treatment at 15℃ for 24 h, the content of fructose was increased. After 48 h treatment at a low temperature of 10℃ to 15℃, the contents of fructose, glucose, trehalose and sorbitol were increased. These results provide a reference for revealing the cold tolerance mechanism of A. lucorum and its forecasting.

Key words: Apolygus lucorum, adult, low temperature, cold hardiness, cold hardiness substances