Effects of Direct Covering with Different Shade Nets on The Tea Canopy Microenvironment and Flavonoid Composition of Tencha

LIU Yijie; CHEN Jiaying; FANG Qiting; YE Jianhui; JIN Zijing

doi:10.13305/j.cnki.jts.2026.04.009

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Journal of Tea Science ›› 2026, Vol. 46 ›› Issue (4) : 637-650. DOI: 10.13305/j.cnki.jts.2026.04.009

Effects of Direct Covering with Different Shade Nets on The Tea Canopy Microenvironment and Flavonoid Composition of Tencha

LIU Yijie¹, CHEN Jiaying¹, FANG Qiting¹, YE Jianhui¹, JIN Zijing^2,*

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Abstract

Direct covering is widely used in the production of matcha raw material, with the advantages of easy operation, low cost, and compatibility with mechanized management. However, how shade nets with different materials and colors differentially affect the canopy microenvironment and flavonoid biosynthesis in tea plants remains unclear. In the present study, eight shade nets varying in material and color were applied to the tea cultivar ‘Longjing 43’ in the field to investigate their effects on the canopy microenvironment and flavonoid accumulation in tencha. The results show that direct covering primarily regulated the canopy microenvironment through changes in ultraviolet (UV) radiation, air humidity, and leaf temperature beneath the cover. Net shade percentage was the major determinant of UV intensity under the net. A black inner surface was more effective in reducing leaf temperature, whereas a white outer surface or aluminum-foil material decreased net surface temperature and heat accumulation, thereby lowering the risk of leaf scorching. All covering treatments generally reduced flavonoid accumulation in the processed tencha, with total catechins decreasing by 16.4%-33.6% and total flavonol glycosides by 23.8%-43.3%. Correlation analysis based on both absolute values and treatment-induced changes further demonstrates that reduced UV radiation was the major driver of the decline in flavonoids, particularly flavonol glycosides, whereas a moderate increase in leaf temperature promoted the accumulation of catechins and quercetin glycosides. Therefore, when producing matcha raw materials under direct covering, shade-net types that combine a high shading rate with good heat dissipation properties should be prioritized,in order to both reduce the UV intensity beneath the net and control leaf temperature. This study provided a theoretical basis for optimizing shading practices and designing novel shade nets for the targeted quality regulation of matcha raw materials.

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direct cover / canopy microenvironment / tencha / catechins / flavonol glycosides

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LIU Yijie, CHEN Jiaying, FANG Qiting, YE Jianhui, JIN Zijing. Effects of Direct Covering with Different Shade Nets on The Tea Canopy Microenvironment and Flavonoid Composition of Tencha[J]. Journal of Tea Science. 2026, 46(4): 637-650 https://doi.org/10.13305/j.cnki.jts.2026.04.009

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