Abstract
The relationships between respiration rates and the content of protein nitrogen and high-energy phosphate were investigated in ripening avocado and tomato fruits. The climacteric rise in respiration rate was accompanied by a rise in total high-energy phosphate in avocados ripened after picking; in tomatoes ripening on the plant the change in total high-energy phosphate was not significant_ The ratio of protein nitrogen to total nitrogen increased during the climacteric rise in both fruits. It is concluded that, while the rates of respiration and synthetic processes may be controlled by the phosphate transfer system, the evidence suggests that uncoupling of respiration and phosphorylation does not explain the respiratory climacteric.