Chemotaxonomy of section Leuce poplars by GC-MS of bud exudate

GC-MS analysis of bud exudate composition of a number of poplars of the section Leuce indicated that Populus alba, P. grandidentata and P. tomentosa were similar in secreting bud exudate containing only hydrocarbon material whereas P. sieboldii, P. tremula and P. tremuloides secreted bud exudate which also included phenolics. The latter three species were distinct from other poplars in secreting an exudate containing flavanones produced only by the first steps of flavonoid biosynthesis, such as naringenin and its methyl ethers, sakuranetin and isosakuranetin, together with their chalcones. Principal component analysis indicated that there are hybrids which are not clearly distinct morphologically from one of the parent species.