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[摘要] To investigate the development and distribution of roots from young tea plant to the mature one in the field, the roots of Yabukita variety in 1969 were grubbed up every year and investigated over 1O years by the soil-block washing method. 1. The roots of 3 years old tea plant were grown at the central part of space (150cm) between hedges. Then those of 4 years old plant reached to a depth of 60-75 cm at the central part of the space between hedges, and thick roots were grown under the trunk. Furthermore, the thick roots of 6 years old plant reached to a depth of 15-30 cm just under the trunk, and the slender roots reached to a depth of 90-105 cm at the central part of space between hedges. The medium roots of mature tea plant of 7 years old reached to a depth of 90-105 cm like the slender roots. After 8 years, each root part increased in the above mentioned rooting zone. 2. About the distribution ratio of three roots parts, slender, medium and thick, in soil, any characteristic tendency was not seen in the vertical distribution of them, but the interesting tendencies were seen in the horizontal distribution. Namely, in the young tea plants slender roots were distributed denser under the trunk than the central part of space between hedges, and in case of 7 years old plants the about same distributions ratio was obtained in all horizontal parts. Eight years after planting, slender roots developed thicker at the central part of space between hedges than under the trunk. 3. The correlation coefficients between the age of a clonal plant and the development of its roots were significantly positive in case of thick and medium one, while in case of slender roots the correlation was not significant. 4. The correlation coefficient between the development of tea roots and growth of aerial parts was significantly positive, and the more the growth of aerial parts the more the development of roots. The T/R ratio of tea plant was shown as over 2.0 in case of young tea plant, but that of mature plant was about 1.5.

[学科分类] 农业科学（综合）