Changes in Growth and Polyphenol Content of the Rare Plant Persicaria chinensis Cultivated in a Greenhouse During the Growth Period

The growth characteristics and changes in major polyphenol content of the rare plant Persicaria chinensis cultivated under greenhouse conditions were investigated to evaluate its potential for large-scale cultivation and industrial use. The fresh and dry weights of the leaves and stems were measured monthly from May to October, and the corilagin, ellagic acid, geraniin, and neochlorogenic acid contents were analyzed. Leaf fresh and dry weights peaked in June (11.73 ± 4.74 g and 3.02 ± 1.22 g, respectively) and increased again in August thereafter, and subsequently decreased, whereas stem fresh and dry weights continuously increased throughout the cultivation period, reaching 20.06 ± 3.88 g and 7.68 ± 1.55 g, respectively, in October. The polyphenol content in leaves was generally highest in June and then declined. In September, the contents of corilagin and ellagic acid showed marked increases, reaching 10.34 ± 4.13 mg/g and 7.26 ± 3.78 mg/g, respectively. In the stems, the polyphenol content was lower than that in the leaves and showed a decreasing trend after the early cultivation stage. Correlation analysis revealed weak relationships between biomass and polyphenol content in the leaves, whereas strong positive correlations among polyphenols and negative correlations between stem growth and polyphenol content were observed in the stems. These results demonstrate that stable greenhouse cultivation of P. chinensis and the accumulation of functional compounds are feasible and provide fundamental information for the development of cultivation strategies, including appropriate fertilization and environmental management, aimed at functional raw material production.