Abstract: Ten secondary metabolites in phloem of different strains of poplars were extracted by different chemical methods and their contents were determined. The effect of different treatment process for samples on the extraction efficiency of tannin, phenols and phenolic acids was studied in detail. The results showed that the contents of phenol and pyrocatechol in Populus alba×P.berolinensis were maximum, while these values were minimum in P. nigra. The temperature of sample preparation had influence on the extraction efficiency of tannin. It was found that the sample treated at 75℃ had the optimal extraction result for tannin, phenol and phenolic acid constituents. In addition, the experimental results also indicated that there were no alkaloids in poplar phloem or their contents were too low to be detected within the detection limit of instrument.

Key words: Poplar, phloem, extraction, secondary metabolites