Relationships of Populus × acuminata and Populus × generosa with their parental species examined by gas chromatography – mass spectrometry of bud exudates

Analysis by gas chromatography – mass spectrometry of bud exudates of Populus deltoides and Populus trichocarpa showed that they each contained a number of different compounds. Exudates of P. trichocarpa contained dihydrochalcones and sesquiterpenols, which were absent from the exudate of P. deltoides, but lacked the flavones, flavanones, and flavanonols present in the exudate of P. deltoides. Exudates of their hybrid, P. × generosa (P. × interamericana), contained compounds typical of both parent plants. Bud exudates of Populus angustifolia and Populus sargentii were qualitatively similar in their flavonoid composition but the exudate of P. angustifolia contained in addition caffeate esters, which were absent from P. sargentii. The exudate from the hybrid P. × acuminata was intermediate. Bud exudates of P. angustifolia and P. × acuminata were more like those of P. deltoides and P. sargentii (section Aigeiros) than they were to those of P. trichocarpa (section Tacamahaca). It is therefore suggested that P. angustifolia and P. × acuminata might be more correctly classified together with P. sargentii and P. deltoides within the section Aigeiros. Key words: Populus, bud exudate, chemotaxonomy, gas chromatography – mass spectrometry.