Oxygen consumption in relation to sorbitol utilization at the termination of diapause in eggs of the silkworm, Bombyx mori

Abstract

Rates of oxygen consumption were followed throughout the entire period of diapause in eggs of Bombyx mori. In non-diapause eggs at 25°C, O 2 uptake was divisible into three phases, corresponding to morphogenetic processes. In diapause eggs at 25°C, O 2 uptake showed a peak (100 μl/g eggs/h) at 1 day and then suddenly dropped to reach a level of 8–10 μl/g eggs/h at 10 days and thereafter. To break diapause, eggs were exposed to 5°C for varying periods. When O 2 uptake was measured at 5°C, it remained at 6 μl/g eggs/h. When eggs were chilled for increasing periods and O 2 uptake was measured immediately after warming to 25°C, the rates increased after a lag phase. In HCl-treated eggs, O 2 uptake increased immediately after acid-treatment. In all cases, highly increasing O 2 uptake at 25°C coincided with termination of diapause. These results were discussed in relation to sorbitol utilization at the termination of diapause.