The reduction of tea quality caused by irrational phosphate application is associated with anthocyanin metabolism

Abstract

Phosphorus (P) is the second most limiting nutrient for plant growth. Previous studies suggested that P substantially affects the yield and quality of tea by affecting root growth, the decomposition and metabolism of minerals and metabolites in plants. Thus, the environmental pollution and degradation of crop quality caused by irrational fertilization is of increasing interest for researchers worldwide. To understand the effects of P fertilization on tea quality and metabolism of key quality components, three P fertilization levels (excessive, appropriate, and deficient application) were applied to tea plants using pot experiments. Content of P, potassium, polyphenols, amino acids and anthocyanins in the leaves or soil were quantified. The sensory quality of tea infusion was reduced under irrational (excessive or deficient) P fertilization. Under P deficiency, the total content of polyphenols and anthocyanins in the leaves were strongly increased compared with those of the control. A high soil P content (excessive) inhibited polyphenol accumulation, but induced the accumulation of certain anthocyanins, such as peonidin-3-O-sambubioside-5-O-glucoside and peonidin-3-O-5-O-(6-O-p-coumaryl)-diglucoside. These results suggest that the reduction of tea quality caused by irrational P application is associated with anthocyanin metabolism, which provides a scientific basis for improving P fertilization strategies in tea plantations.