Abstract
The effect of 85% shading of mature tea plants for three months in winter, or the first or latter half of this period, on the carbohydrate content of the plant and productivity of the first crop of tea were examined by periodically measuring the contents of soluble sugar and starch in each organ, shoot growth, yield and quality of new shoots. Without shading, sugar, produced by photosynthesis was fully supplied and starch was accumulated in the middle roots and thick roots until late February, and then in the branches until budding time. By shading for 3 months from early January to early April, starch accumulation in the middle roots, branches and thick roots were delayed due to insufficient supply of sugar from source leaves. The contents of soluble sugar and starch in each organ at budding time were reduced more severely by shading from early January to late February than from late February to early April. Shading during the latter period, also caused delay of growth and harvest time, decrease in the number of new shoots, and irregular size of new shoots. These results suggested that shading before budding from late February to early April was more suppressive than that in early January to late February, the coldest season, and that the lack of reserve carbohydrate lowered the yield and quality of the first crop of tea.
