Ethylene Production in Seedlings of Chenopodium rubrum, as Influenced by Seedlings Age, Light, and CO2 Concentration1)

Abstract

Summary Ethylene formation in intact seedlings of a short-day plant Chenopodium rubrum was followed in the course of the first 26 d of growth. The highest values of ethylene evolution were found in the youngest (2 1/2-d-old) plants. Ethylene evolution then decreased up to the 4th d as expressed both on dry weight and on one plant basis. Later, ethylene evolution expressed on dry weight basis decreased till the 26th d, while that expressed on one plant basis increased from the 5th d onward, the rate of increase gradually leveling off. The peaks of flowering coincided with periods of low ethylene production, as expressed on dry weight. Light inhibited ethylene production in C. rubrum seedlings. A higher CO, level did not cancel such inhibition. A lower CO 2 level decreased ethylene production in darkness. ACC markedly increased ethylene evolution and this ACC-induced ethylene production is inhibited by light more strongly than that in the absence of ACC. The relationship between the levels of auxin and ethylene and the capacity for flowering is discussed.