Studies On Seasonal Dynamics Of Phenolic Compounds In Poplar

Experiments were carried out to study the seasonal variation of phenolic compounds(total phenol, flavonoids, condensed tannin, lignin, phenolic glycosides) in popular.phenolic compounds contents were normally higher in Populus×'Zhonglin Sanbei 1' than Populus alba×berolinensis. There were significant differences in contents of phenolic compounds among different organs. Phenols contents were the highest in buds, then in bark of trunk, branch bark, and lowest in leaves, whereas it in leaves increased to the same level as in branch bark even trunk bark before senescence of leaves.Phenolic glycoside contents in Populus×'Zhonglin Sanbei 1' were significant lower than that in Populus alba×berolinensis. The differences are significant among different sampling sites of Populus alba×berolinensis. Tremulacin was not detected in Populus×'Zhonglin Sanbei 1'. The contents from high arrive' low generally are bark of trunk, branch bark, buds and leaves.Negative correlations between the contents of total phenol, flavonoid, condensed tannin in leaves and the lowest temperature were significant; Positive correlation between lignin content in leaves and lowest temperature was significant. Negative correlations between the contents of total flavonoid, lignin in branch bark and lowest temperature were significant; Positive correlations between the contents of total phenol, salicortin in branch bark and lowest temperature is significant. Negative correlations between the contents of flavonoid, lignin, salicortin in bark of trunk in Populus alba×berolinensis and lowest temperature were significant; Positive correlation between the total phenol content in trunk bark of Populus alba×berolinensis and lowest temperature was significant.Total phenol, flavonoid and condensed tannin may be actively evolved in the defensive system to low temperature stress; total phenol and condensed tannin in barks might relate to low temperature stress in the period before and after dormancy, while flavonoid and lignin might more relate to low temperature stress in dormant season; The high content in phenolic compounds in buds may relate to the adaptation to low temperature.