Protective effect of melatonin against chlorophyll degradation during the senescence of barley leaves
Article first published online: 5 AUG 2008
© 2008 The Authors. Journal compilation © 2008 Blackwell Munksgaard
Journal of Pineal Research
Volume 46, Issue 1, pages 58–63, January 2009
How to Cite
Arnao, M. B. and Hernández-Ruiz, J. (2009), Protective effect of melatonin against chlorophyll degradation during the senescence of barley leaves. Journal of Pineal Research, 46: 58–63. doi: 10.1111/j.1600-079X.2008.00625.x
- Issue published online: 25 NOV 2008
- Article first published online: 5 AUG 2008
- Received June 3, 2008; accepted July 8, 2008.
- abscisic acid;
- foliar senescence;
- Hordeum vulgare (barley);
Abstract: Melatonin (N-acetyl-5-methoxytryptamine) is a highly conserved molecule whose presence is not exclusive to the animal kingdom. Indeed, numerous studies have demonstrated its presence in plants, where the possible role(s) of this indoleamine is (are) under active investigation. The present work aims to further our knowledge in this respect and presents the results of a study of the effect that melatonin has on foliar senescence. Barley leaves treated with melatonin solutions clearly slowed down the senescence process, as estimated from the chlorophyll lost in leaves. This effect of melatonin was concentration dependent, with an optimal response being obtained at 1 mm melatonin, after 48 hr of incubation in darkness. The already known effects of the phytohormones, kinetin, and abscisic acid, were also assayed. Of the phytohormone and melatonin combinations assayed, 1 mm melatonin presented the best protection against senescence. The levels of endogenous melatonin in control leaves were measured by liquid chromatography with fluorescence detection and in leaves treated with different exogenous melatonin concentrations (to demonstrate the absorption capacity of leaves). The possible physiological implications of this newly revealed action of melatonin in foliar senescence are discussed.