Distribution of tannin cells in persimmon tree and the basic chemical composition of tannins in calluses derived from persimmon leaflets
The astringency of persimmon fruit is caused by tannins (polymeric flavan-3-ols), a type of polyphenol.
Previous studies have revealed that tannins accumulate in tannin cells in the persimmon fruit, but the distribution of tannin cells in the tree has not been clarified yet.
In this preliminary study, leaves and branches with different astringent types, Fuyu (PCNA type) and Hiratanenashi (non-PCNA type), were collected to prepare tissue specimens.
Then, the distribution of tannin cells in the tissues was examined histologically.
In addition, the distribution of tannin cells was also observed in callus induced from leaflets of the same cultivars, and the basic chemical properties of tannins were analyzed by determining the tannin content and by identifying its constituent using TLC or HPLC. The results showed that tannin cells were observed in leaves and branches of persimmon plant, regardless of the cultivar.
In particular, the abundance of tannin cells was observed around the vascular bundles.
Tannin cells were also confirmed in the callus derived from persimmon leaflets of both cultivars, suggesting that any tissues have the ability to produce tannins.
On the other hand, the amounts of tannins in the callus were higher in Hiratanenashi than in Fuyu, which was consistent with the result in the branches and leaves of Hiratanenashi. The basic chemical compositions of tannins in both calluses after thiol degradation were identified as epicatechin (or epigallocatechin gallate), epicatechin gallate, and (+)-catechin of the terminal unit.
The results of our preliminary studies provide an idea for elucidating the chemical properties of tannins for persimmon.
Yamamoto, R., Genda, R., Fukuhara, K., Ogata, T. and Yonemori, K. (2022). Distribution of tannin cells in persimmon tree and the basic chemical composition of tannins in calluses derived from persimmon leaflets. Acta Hortic. 1338, 223-230
DOI: 10.17660/ActaHortic.2022.1338.32
https://doi.org/10.17660/ActaHortic.2022.1338.32
DOI: 10.17660/ActaHortic.2022.1338.32
https://doi.org/10.17660/ActaHortic.2022.1338.32
tissue observation, proanthocyanidin, HPLC analysis, thiolysis
English