Ethylene‐triggered abscisic acid: A principle in plant growth regulation? |
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Authors: | Klaus Grossmann Hauke Hansen |
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Institution: | BASF Agricultural Center Limburgerhof, D-67114 Limburgerhof, Germany;Matern-Feuerbacher-Str. 11, D-71034 Böblingen, Germany |
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Abstract: | The application of auxins to sensitive plant species or their overproduction in transgenic plants stimulates ethylene biosynthesis via induction of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase. Recent studies with auxin herbicides and indole-3-acetic acid (IAA) have revealed that auxin-stimulated ethylene triggers an increase in the biosynthesis of abscisic acid (ABA), which then functions as a second messenger, leading to growth inhibition and senescence. This raises the question of whether ethylene-triggered ABA is restricted to the action of auxin herbicides or whether it is a widespread phenomenon in the normal plant growth regulation. Our own results and a reappraisal of the literature indicate that ethylene-induced ABA may, indeed, play a role in natural physiological phenomena, such as root gravireaction and suppression of lateral bud growth in apical dominance. In addition, it would be worthwhile to investigate whether ethylene-triggered ABA is involved in other processes which coincide with a strong stimulation of ethylene biosynthesis, such as growth inhibition induced by cytokinins and senescence elicited under stress conditions. |
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