Mercury-induced Ethylene Formation and Abscission in Citrus and Coleus Explants

Mercury vapor induces ethylene formation and abscission in Citrus and Coleus explants. Both responses are markedly greater in the absence of CO(2). The stimulation of these metabolically complex processes indicates that the action of mercury vapor is not consistent with the more popular conception of mercury toxicity. This was manifested in its complete failure to disturb respiratory gas exchange, and in the total absence of any necrosis. Accordingly, the effect of mercury appears to be highly specific. The overall significance of these findings is discussed with respect to physiological, environmental, and methodological aspects.