Tannin Contents Of Different Parts Of Kandelia Candel, And Salinity Effect On Tannin Production Of Roots In The Jiulong River Estuary, Fujian, China

Total phenolics(TP), extractable condensed tannins (ECT), bound condensed tannins (BCT), and total condensed tannins (TCT) contents in the different parts of Kandelia candel (young leaves, mature leaves, old leaves, bark of stems, timber of stems, bark of young roots, timber of young roots, bark of old roots, timber of old roots) were determined in the Jiulong River Estuary, Fujian, China in Autumn, 2005. Seedlings of K. candel were cultured under various saline conditions (0‰～40‰) in greenhouse for determining indexes of growth and tannin contents of roots and for watching distributions of tannin cells of roots of K. candel by making parafin slice. The results showed as follows:1. There was a significant linear correlation between total phenolics for the two different standards for K. candel. The results showed that about twice as much total phenolics content when the purified tannins standard was used rather than the tannic acid standard.2. TP content of different parts of K. candel ranged from 102.64±1.42 to 365.72±50.45 mg·g^-1 with the highest in bark of stems and the lowest in timber of stems. TP content was higher in bark of young roots than timber of young roots. High TP content in bark are demanded to provide defense in complex environment. Not significant difference was found between bark and timber of old roots. TP content was higher in old leaves than young and mature leaves. ECT and TCT contents followed the similar pattern. ECT content was significantly higher than BCT content.3. At different salinity culture, the growth of roots of K. candel was promoted in low salinity and was restrained in high salinity.4. During the period of different salinity culture (from 60 to135 d), TP content fluctuated with increasing salinity, with the highest TP content occurring in high salinity. ECT and TCT contents fluctuated under different salinity conditions with a consistent pattern. ECT contents were significantly higher than BCT contents. At culture salinity of 15‰, the distribution of tannins in different parts of roots in the same period from 75 to 105 d followed the identical pattern: the closer the roots tip is, the higher the TP, ECT, BCT, and TCT contents are.5. At culture salinity of 15‰, the distributions of tannins of roots in different periods from 15 to 135 d followed the identical pattern: TP content descended(198.71±12.60～37.42±1.13 mg·g^-1) from 15 to 90 d and then ascended(56.47±2.76～75.23±5.65 mg·g^-1) from 90 to 135 d. ECT and TCT contents fluctuated with a consistent pattern. ECT content was significantly higher than BCT content.6. Tannin cells of roots of K. candel in different salinity culture were observed with microscope by making parafin slice. Most tannin cells concentrated in surface lays of roots. The closer the roots tip is, the wider the distribution of tannin cells. The distribution of tannin cells of root tip was wider in high salinity (over 20‰) than in low salinity.