Melatonin promotes water-stress tolerance, lateral root formation, and seed germination in cucumber (Cucumis sativus L.)
Article first published online: 3 JUL 2012
© 2012 John Wiley & Sons A/S
Journal of Pineal Research
Volume 54, Issue 1, pages 15–23, January 2013
How to Cite
Zhang, N., Zhao, B., Zhang, H.-J., Weeda, S., Yang, C., Yang, Z.-C., Ren, S. and Guo, Y.-D. (2013), Melatonin promotes water-stress tolerance, lateral root formation, and seed germination in cucumber (Cucumis sativus L.). Journal of Pineal Research, 54: 15–23. doi: 10.1111/j.1600-079X.2012.01015.x
- Issue published online: 6 DEC 2012
- Article first published online: 3 JUL 2012
- Accepted manuscript online: 31 MAY 2012 11:45AM EST
- Received March 27, 2012; Accepted May 25, 2012.
- lateral root;
- water stress
Abstract: A comprehensive investigation was carried out to determine the changes that occurred in water-stressed cucumber (Cucumis sativus L.) in response to melatonin treatment. We examined the potential roles of melatonin during seed germination and root generation and measured its effect on reactive oxygen species (ROS) levels, antioxidant enzyme activities, and photosynthesis. Melatonin alleviated polyethylene glycol induced inhibition of seed germination, with 100 μm melatonin-treated seeds showing the greatest germination rate. Melatonin stimulated root generation and vitality and increased the root:shoot ratio; therefore, melatonin may have an effect on strengthening cucumber roots. Melatonin treatment significantly reduced chlorophyll degradation. Seedlings treated with 100 μm melatonin clearly showed a higher photosynthetic rate, thus reversing the effect of water stress. Furthermore, the ultrastructure of chloroplasts in water-stressed cucumber leaves was maintained after melatonin treatment. The antioxidant levels and activities of the ROS scavenging enzymes, i.e., superoxide dismutase, peroxidase, and catalase, were also increased by melatonin. These results suggest that the adverse effects of water stress can be minimized by the application of melatonin.