Effect of carbon dioxide and light on ethylene production in intact sunflower plants.

High CO(2) concentration (0.5%) increased the rate of ethylene production, measured in a continuous flow system, in intact sunflower (Helianthus annuus L.) plants. However, the rate of ethylene production subsided to near control levels after approximately 24 hours. The effect of high CO(2) could only be observed in light. Although high CO(2) concentration had no effect on the rate of ethylene production in darkness, prolonged exposure (approximately 16 hours) of plants to high CO(2) in the dark prevented the increase in ethylene production when the plants were exposed to light and high CO(2).