柿果实和叶片中可溶性单宁含量的年变化

Annual variation of soluble tannin in the fruits and leaves of persimmon

为掌握不同类型柿资源果与叶中可溶性单宁含量的年动态变化规律,以野生柿、完全涩柿（PCA）、完全甜柿（PCNA）和不完全甜柿（PVNA）4种类型11份样品为试材,采用Folin-Ciocalteu法在不同生长时期对其果实和叶片中可溶性单宁的含量进行测定。结果表明：柿果实和叶片中含有丰富的可溶性单宁,监测期内其含量分别在0~70.92 mg/g和5.99~65.49 mg/g波动;不同品种果实可溶性单宁含量均在生长初期最高,随着果的生长发育而逐渐降低,与果质量、纵径和横径值呈极显著的负相关关系,说明单宁细胞稀释效应可能是其脱涩的主要原因;不同品种柿叶可溶性单宁含量差异较小,动态变化规律基本一致,含量高峰时期集中在7月中旬至8月上旬,如以可溶性单宁为目标成分进行柿叶资源的开发利用,则应在此时集中采收。

In order to reveal annual variation of soluble tannin contents in the fruits and leaves of persimmon, eleven va-rieties of samples were measured by Folin-Ciocalteu method including PCA, PCNA, PVNA and wild varieties. The re-sults showed that there were abundant soluble tannin in persimmon fruits and leaves, and the contents fluctuated in therange of 0-70.92 mg/ g and 5.99-65.49 mg/ g during the entire monitored period, respectively. The contents of solubletannin in fruits were decreased with the growth, and there were significant negative correlations with fresh weight, verti-cal diameter and transverse diameter, which indicated that the tannin cells dilution by fruit enlargement account for theloss of astringency on the tree. The soluble tannin contents in 11 varieties of persimmon leaves showed small difference andthe annual variety trends were almost identical. In addition, the results also suggested that the optimum harvesting timepromoting effective utilization of soluble tannin in persimmon leaves was from middle July to early August.