Seasonal Variation of Tannin and Nutrient in Aegiceras corniculatum Leaves in Zhangjiang Mangrove Ecosystem

摘要

Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensedtannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT) and nitrogen contents in sun andshade leaves of Aegiceras corniculatum were studied in the Zhangjiang Estuary, Fujian Province, China. The contents ofTP, ECT and TCT in the sun leaves were significantly higher than those in the shade leaves through the season. The Ncontent in sun leaves was higher than that in shade leaves in the autumn, while it was lower in the summer, and there wasno significant difference in the winter and spring. With the respect to the P through the year, P content in the sun leaveswas different between seasons, with the highest in winter and the lowest in summer. In addition, the TP:N and ECT:Nratios in sun leaves were significantly higher than those in shade leaves except in autumn. High tannin levels and TP:Nand ECT:N ratios in the sun leaves not only can reduce oxidative stress, but also improve the ability of resisting plantdiseases and insect pests.