Species height and root symbiosis, two factors influencing antiherbivore defense of woody plants in East African savanna

In East African savanna we found that leaves of mature tree species with symbiotic N₂ fixation contained lower concentrations of polyphenols than leaves of species without this symbiosis. We suggest that the root symbiosis is costly to the plant in terms of photosynthate that otherwise could be used in chemical defense. Further, a negative relationship between concentration of polyphenols and the height of the species was found, independent of their ability to fix N₂. These findings suggest that root symbioses and apparency to herbivory are important factors mediating the production of chemical defenses in plants.