Seasonal Changes in the Depression of Respiratory Rate of Rootlets Induced by Pruning in Tea Plants

[摘要] In an attempt to throw the light on pruning effects in tea cultivation, the relationship between time of pruning and changes in the respiratory rate of rootlets were investigated with a special reference to the content of storage carbohydrates in roots and the growth temperature. One year-old tea plants (Camellia sinensis (L.) O. Kuntze) grown in plastic pots in field were pruned remaining 1/2 or 1/4 of plant height (1/2 pruning or 1/4 pruning). The respiratory rate (oxygen absorption) of rootlets was measured with an electrode. The depression of respiratory rate of rootlets induced by pruning gradually grew stronger from March to July, and then gradually became weaker to November (Fig. 2). The depression was larger in 1/4 pruning plants than in 1/2 pruning plants (Figs. 1 and 2), and was larger in cvs Yabukita and Kurasawa than in cvs Fujimidori and Okumusashi (Table 1). There was no relationship between seasonal changes in the depression of respiratory rate of rootlets induced by pruning and the content of storage carbohydrates in roots (Figs. 3, 4 and 5). On the other hand, seasonal changes in the depression rate of rootlets induced by pruning and temperature at underground of 10 cm were positively related ; correlation coefficients were 0.941 for cv Yabukita and 0.892 for cv Fujimidori (both are siginificant at 1 % level) (Figs. 6 and 7). When the 1/2 pruning was done to the plants grown under two kinds of day-night temperature regimes, 25-20°C and 15-10°C respectively, the depression of respiratory rate of rootlets was larger in 25-20°C than in 15-10°C (Fig. 8 and Table 2). From these results, it was demonstrated that the depression of respiratory rate of rootlets induced by pruning was larger in summer than in other three seasons and the depression was influenced by temperature at the time when pruning was done rather than content of storage carbohydrate in roots.

[学科分类] 农业科学（综合）