Post-anoxic effects of ethanol in rhizomes of Glyceria maxima (Hartman) Holmberg, Iris germanica L. and Phragmites australis (Cav.) Trin.

In rhizomes of the wetland species Glyceria maxima and Phragmites australis oxygen uptake is less sensitive to ethanol than in the rhizomes of the dryland plant Iris germanica. Applied ethanol in the same concentrations that accumulate in I. germanica during a 48 h anaerobic treatment, exert a strong inhibitory effect on the oxygen uptake of the rhizomes under air. During the same time span under anoxia, I. germanica produces more ethanol than the two wetland species. During post-anoxia the degradation rate of internal ethanol is rather low in comparison with its synthesis under anoxia. This behaviour is closely associated with the higher alcohol dehydrogenase activity in the direction of ethanol production, as compared with the activity in the direction of ethanol decomposition. However, post-anoxic rhizomes of I. germanica also show an unhindered rise in acetaldehyde concentration. This is not true for the post-anoxic wetland plant rhizomes. Therefore, post-anoxic injury by elevated acetaldehyde concentrations in rhizomes of I. germanica cannot be excluded