Synchronous flowering of the rubber tree (Hevea brasiliensis) induced by high solar radiation intensity
Article first published online: 23 APR 2007
Volume 175, Issue 2, pages 283–289, July 2007
How to Cite
Yeang, H.-Y. (2007), Synchronous flowering of the rubber tree (Hevea brasiliensis) induced by high solar radiation intensity. New Phytologist, 175: 283–289. doi: 10.1111/j.1469-8137.2007.02089.x
- Issue published online: 23 APR 2007
- Article first published online: 23 APR 2007
- Received: 10 February 2007 Accepted: 9 March 2007
- Hevea brasiliensis (rubber tree);
- meteorological factors;
- solar radiation intensity;
- synchronous flowering;
- tropical trees
- • How tropical trees flower synchronously near the equator in the absence of significant day length variation or other meteorological cues has long been a puzzle. The rubber tree (Hevea brasiliensis) is used as a model to investigate this phenomenon.
- • The annual cycle of solar radiation intensity is shown to correspond closely with the flowering of the rubber tree planted near the equator and in the subtropics. Unlike in temperate regions, where incoming solar radiation (insolation) is dependent on both day length and radiation intensity, insolation at the equator is due entirely to the latter.
- • Insolation at the upper atmosphere peaks twice a year during the spring and autumn equinoxes, but the actual solar radiation that reaches the ground is attenuated to varying extents in different localities. The rubber tree shows one or two flowering seasons a year (with major and minor seasons in the latter) in accordance with the solar radiation intensity received.
- • High solar radiation intensity, and in particular bright sunshine (as distinct from prolonged diffuse radiation), induces synchronous anthesis and blooming in Hevea around the time of the equinoxes. The same mechanism may be operational in other tropical tree species.