Effects of Carbon Dioxide on Ethylene Production and Action in Intact Sunflower Plants

Abstract

A continuous flow system was used to study the interactions between CO2 and ethylene in intact sunflower plants. An increase in the concentration of CO2 above the ambient level (0.033%) in the atmosphere surrounding the plants increased the rate of ethylene production, and a decrease in CO2 concentration resulted in a decrease in the rate of ethylene production. The change in the rate of ethylene production was evident within the first 15 min of the CO2 treatment. Continuous treatment with CO2 was required to maintain increased rate of ethylene production. The rate of CO2 fixation increased in response to high CO2 treatment up to 1.0%. Further increases in CO2 concentration had no additional effect on CO2 fixation. CO2 concentrations > 0.11% induced hyponasty of the leaves; treatment with 1 .mu.l/l ethylene induced epinasty of the leaves.