Influence of Direct Covering Period on the Growth and the Constituents in New Shoots of First Crop of Tea Bush

Abstract

To clarify the effect of covering practice befor tea plucking, the characteristics and the constituents in new shoots of first crop of tea plants were examined with different periods and opening times of direct covering on the bush.The longer period of direct covering brought the decrease of number of new shoots, weight of 100 new shoots, and weight of new shoots. The color of direct-covered-leaves got deeper than without covering at 3-5days after direct covering, and this result became much clearer in 10 days.The contents of total nitrogen and free amino acids in new shoots were higher than without covering at 3-5days after direct covering, and after that, it was not influenced by the period of covering. The content of tannin in new shoots was lower than without covering at 3-5days after direct covering, and it was decreased as started to cover earlier. On the other hand, the content of neutral detergent fiber in new shoots was not influenced by direct covering.

Effect of shading intensity on morphological and color traits and on chemical components of new tea (Camellia sinensis L.) shoots under direct covering cultivation

“…The SPAD values reached approximately 40 and 50 under open and covering culture respectively during the first cropping season in Y1. These results were similar to those reported by Chutani and Takewaka . By contrast, Inaba et al .…”

“…In our previous study, 3 epigallocatechin (EGC) contents of new tea shoots became lower with higher shading condition, whereas theanine (Thea) content was higher under shading condition during the first cropping season. Other previous studies [4][5][6] also have reported both decrease in the catechin contents and increase in the amino acid contents under shading culture. For further work, it is necessary to reveal shading intensity effects on the morphological and color traits of new shoots and on the chemical components to understand plasticity of new tea shoot traits to covering culture, because the relations among these traits are considered a trade-off relation called the economics spectrum 12 relating to plant productivity.…”

“…These results were similar to those reported by Chutani and Takewaka. 5 By contrast, Inaba et al 34 reported that SPAD values of new tea leaves decrease under extremely dark conditions, although those of white leaf tea cultivars or lines increased. Irradiance effects on SPAD values and chlorophyll contents can vary depending on radiation intensity and cultivar.…”

“…2,3 These characteristics have received considerable attention because of their relationships with both quality of manufactured tea product and productivity in raw material shoots. Chemical components [3][4][5][6][7][8][9][10] and color traits 5,6,11 of new tea shoots under shading culture have been intensively studied. However, the morphological traits of new tea shoots have received less attention.…”

Phenotypic Markers Reflecting the Status of Overstressed Tea Plants Subjected to Repeated Shade Cultivation

“…The most typical response to shading treatment is the darker green color of leaves owing to increased chlorophyll content (Sano et al, 2018). Previous studies (Chutani and Takewaka, 2006;Kobayashi et al, 2011;Matsunaga et al, 2016;Sano et al, 2018) have additionally revealed that shading treatment causes an increase in the contents of amino acids, especially theanine, and a decrease in the contents of catechins, especially epigallocatechin. The contents of free amino acids and chlorophyll are extremely important determinants of tea quality and price.…”