RELATIONSHIPS OF POPULUS-XACUMINATA AND POPULUS-XGENEROSA WITH THEIR PARENTAL SPECIES EXAMINED BY GAS-CHROMATOGRAPHY - MASS-SPECTROMETRY OFBUD EXUDATES

Analysis by gas chromatography - mass spectrometry of bud exudates of Populus deltoides and Populus trichocarpa showed that they each contai ned a number of different compounds. Exudates of P. trichocarpa contai ned dihydrochalcones and sesquiterpenols, which were absent from the e xudate of P. deltoides, but lacked the flavones, flavanones, and flava nonols present in the exudate of P. deltoides. Exudates of their hybri d, P. x generosa (P. x interamericana), contained compounds typical of both parent plants. Bud exudates of Populus angustifolia and Populus sargentii were qualitatively similar in their flavonoid composition bu t the exudate of P. angustifolia contained in addition caffeate esters , which were absent from P. sargentii. The exudate from the hybrid P. x acuminata was intermediate. Bud exudates of P. angustifolia and P. x acuminata were more like those of P. deltoides and P. sargentii (sect ion Aigeiros) than they were to those of P. trichocarpa (section Tacam ahaca). It is therefore suggested that P. angustifolia and P. x acumin ata might be more correctly classified together with P. sargentii and P. deltoides within the section Aigeiros.