This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Grodzinski, B. Articles by Horton, R. F. Search for Related Content PubMed PubMed Citation Articles by Grodzinski, B. Articles by Horton, R. F. Agricola Articles by Grodzinski, B. Articles by Horton, R. F.

Articles

Light Stimulation of Ethylene Release from Leaves of Gomphrena globosa L. ¹

Department of Horticultural Science, University of Guelph, Guelph, Ontario N1G 2W1 Canada, Department of Botany and Genetics, University of Guelph, Guelph, Ontario N1G 2W1 Canada

The effect of light and CO₂ on both the endogenous and 1-aminocyclopropane-1-carboxylic acid (ACC)-dependent ethylene evolution from metabolically active detached leaves and leaf discs of Gomphrena globosa L. is reported. Treatment with varying concentrations of ACC did not appear to inhibit photosynthesis, respiration, or stomatal behavior. In all treatments, more ethylene was released into a closed flask from ACC-treated tissue, but the pattern of ethylene release with respect to light/dark/CO₂ treatments was the same.

Leaf tissue in the light with a source of CO₂ sufficient to maintain photosynthesis always generates 3 to 4 times more ethylene than tissue in the dark. Conversely, the lowest rate of ethylene release occurs when leaf tissue is illuminated and photosynthetic activity depletes the CO₂ to the compensation point. Ethylene release in the dark is also stimulated by CO₂ either added to the flask as bicarbonate or generated by dark respiration. Ethylene release increases dramatically and in parallel with photosynthesis at increasing light intensities in this C₄ plant. Ethylene release appears dependent on CO₂ both in the light and in the dark. Therefore, it is suggested that the important factor regulating the evolution of ethylene gas from leaves of Gomphrena may be CO₂ metabolism rather than light per se.

¹ Supported by grants from Ontario Ministry of Agriculture and Food to B. G., and the Natural Science and Engineering Research Council, Canada, to B. G. and R. F. H.