Jghm. Rijnders et al., ETHYLENE ENHANCES GIBBERELLIN LEVELS AND PETIOLE SENSITIVITY IN FLOODING-TOLERANT RUMEX PALUSTRIS BUT NOT IN FLOODING-INTOLERANT R-ACETOSA, Planta, 203(1), 1997, pp. 20-25
The role of gibberellin (GA) and ethylene in submergence-induced petio
le elongation was studied in two species of the genus Rumex. Analysis
of endogenous Gas in the flooding-tolerant Rumex palustris Sm. and the
intolerant Rumex acetosa L. by gas chromatography-mass spectrometry s
howed for both species the presence of GA(1), GA(4), GA(9), GA(19), GA
(20) and GA(53). Gas chromatography-mass spectrometry analysis of R. p
alustris petiole tissue of submerged plants showed an increase in leve
ls of 13-OH GAs, especially GA(1), compared with drained plants. This
effect could be mimicked by application of 5 mu L L-1 ethylene. In R,
acetosa, no differences between levels of GAs in drained or submerged
plants were found. In R. palustris, both submergence and ethylene trea
tment sensitized petioles to exogenous gibberellic acid (GA(3)). In X.
acetosa the effect was opposite? i.e. submergence and ethylene de-sen
sitized petioles to GA(3). Our results demonstrate the dual effect of
ethylene in the submergence response related to flooding tolerance, i.
e. in the flooding-tolerant R. palustris ethylene causes an increased
concentration of and sensitivity to GA with respect to petiole elongat
ion while in the intolerant R. acetosa ethylene reduces growth indepen
dent of GAs.