Effects of tea-plum intercropping on growth of tea trees and the quality of autumn green tea

【Objective】The effects of intercropping of tea-plums on the growth of tea trees and the quality of autumn green tea were studied to provide theoretical basis for the feasibility of intercropping of plums in tea gardens and to improve the utilization rate of summer and autumn tea. 【Method】In this study, Fuxuan 9 was the test variety, the growth potential indexes of tea trees(such as weight of 100 buds and the number of bud per 100 g) in monoculture tea garden and intercropping tea garden were measured, and main chemical compositions contents of autumn green tea, such as tea polyphenols, free amino acids, catechins, flavonoids, amino acid components and aroma components were analyzed by spectrophotometry, high performance liquid chromatography(HPLC) and gas chromatography-mass spectrometer(GC-MS).【Result】The humidity, weight of 100 buds, and the contents of free amino acid, water extracts, tyrosine, histidine and theanine in tea-plum intercropping garden were significantly higher than that in control tea garden(P<0.05, the same below); while the number of bud number per 100 g, the contents of tea polyphenols, flavone, and ester type catechins in intercropping garden were significantly lower. A total of 205 aroma components were identified from all samples, including aldehydes, esters, alcohols, alkenes, aromatics, ketones, alkanes, and heterocyclic compounds, among them, esters and alkanes had the highest relative content. Principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA) showed that the relative contents of methyl salicylate, linalool and linalool oxide I(pyran),(Z)-3-hexen-1-ol, which contributed to floral aroma, as well as relative contents of(Z)-hexanoic acid 3-hexenyl ester, benz aldehyde, hexanal and benzeneacet aldehyde, which contributed to chestnut aroma of green tea, were significantly higher in intercropping garden. Correlation analysis showed that there was extremely significant positive correlation between polyphenols, flavone, ester type catechins with astringency and bitterness intensity, while had significant negative correlation with umami, mellow and sweetness taste. Water extract, theanine and tyrosine had a significant positive correlation with umami, mellow and sweetness taste, while significant negative correlation with astringency and bitterness intensity. Moreover, 23 aroma compounds, such as methyl salicylate, linalool, benz aldehyde and hexanal had a significant positive correlation with floral aroma and chestnut aroma, while significant negative correlation with fresh and grassy green. 【Conclusion】Intercropping plum in tea gardens enhances the growth potential of tea trees, improves the microclimate of tea gardens, reduces the bitterness taste of autumn green tea, improves freshness, chestnut aroma, and floral aroma, and greatly improves overall sensory quality. This provides a reference for further promoting and applying the tea-plum intercropping model in the southern Sichuan tea region.