Histochemical study of secretory structures in oaks and other isoprenoid emitting plant species

A histochemical study revealed that isoprenoid emission from Quercus leaves is not associated with the presence of specialised secretory structures for the production and storage of these compounds. Glandular hairs of young and mature leaves of the isoprene emitter Quercus pubescens, and of young leaves of the monoterpene emitter Quercus ilex, when present, did not contain isoprenoids. These results are consistent with the finding that isoprenoids emitted by Quercus species are directly produced from photosynthetic carbon, which is rapidly lost in the atmosphere. By contrast, large pools of isoprenoids in the ducts of Pinus and in the secretory cavities of Citrus were detected.