Tea polyphenols dominate the short-term tea (Camellia sinensis) leaf litter decomposition

Abstract

Polyphenols are one of the most important secondary metabolites, and affect the decomposition of litter and soil organic matter. This study aims to monitor the mass loss rate of tea leaf litter and nutrient release pattern, and investigate the role of tea polyphenols played in this process. High-performance liquid chromatography (HPLC) and classical litter bag method were used to simulate the decomposition process of tea leaf litter and track the changes occurring in major polyphenols over eight months. The release patterns of nitrogen, potassium, calcium, and magnesium were also determined. The decomposition pattern of tea leaf litter could be described by a two-phase decomposition model, and the polyphenol/N ratio effectively regulated the degradation process. Most of the catechins decreased dramatically within two months; gallic acid (GA), catechin gallate (CG), and gallocatechin (GC) were faintly detected, while others were outside the detection limits by the end of the experiment. These results demonstrated that tea polyphenols transformed quickly and catechins had an effect on the individual conversion rate. The nutrient release pattern was different from other plants which might be due to the existence of tea polyphenols.

摘要

目的

通过测定茶树叶片的分解速率及养分释放规律, 研究茶多酚在茶树叶片分解过程中的作用。

创新点

测定了茶树叶片在茶园地表的分解速率和养分释 放规律,并确定了茶多酚/氮素比值在茶树叶片短 期分解过程中的主导作用。首次利用高效液相色 谱法监测了分解过程中儿茶素的变化规律。

方法

采集成熟的茶树叶片,在室内风干后利用分解袋 法测定其分解速率。分解袋放置于茶园地表用于 模拟田间条件,逐月收集分解样品。实验结束后, 测定各月份叶片的干重残留量、月均干重损失 率、多酚等有机组分含量以及各元素含量。

结论

茶树叶片的干物质损失规律可以“两相分解模型” 进行描述,茶多酚/氮素比值是调控分解速率的主 要因素。分解过程中,茶多酚的转换十分迅速, 同时儿茶素单体的结构影响其分解速率:大部分 的儿茶素单体在分解初始两个月内迅速消失,没 食子酸(GA)、儿茶素没食子酸酯(CG)、儿 茶素(GC)在分解后期少量检出,而其他儿茶素 已不在检测限内。茶树叶片中大量多酚的存在及 其特有性质可能影响着叶片中的养分释放过程。