PLANT PHYSIOLOGY , Vol 105, Issue 2 497-507, Copyright © 1994 by American Society of Plant Biologists
|
DEVELOPMENT AND GROWTH REGULATION |
The Abscisic Acid Induction of a Novel Peroxidase Is Antagonized by Cytokinin in Spirodela polyrrhiza L
K. Chaloupkova and C. C. Smart
Institute of Plant Sciences, Plant Biochemistry and Physiology, ETH Zurich, Universitatsstrasse 2, CH-8092 Zurich, Switzerland
The growth regulator abscisic acid (ABA) can be used to induce dormant bud
structures (turions) in the duckweed Spirodela polyrrhiza L. In this paper
we show that during this process, ABA rapidly induces elevated levels of
mRNA transcripts encoding a novel basic peroxidase. In addition, we show
that in the presence of the cytokinin kinetin the maintained increase is
attenuated. Kinetin not only totally inhibits the induction of turions by
ABA but also alleviates ABA-induced growth inhibition. This antagonism of
an ABA-induced gene by a cytokinin correlates with an easily observable
antagonistic effect of these two hormones on plant morphogenesis. These
data contribute to a growing body of evidence linking growth regulators
with changes in peroxidase gene expression and to the concept of pairs of
hormones playing antagonistic roles during plant development. Finally, we
discuss the possible functions that peroxidases could have during
ABA-induced turion formation and growth inhibition.
