Cesium uptake and translocation from tea cutting roots (Camellia sinensis L.)

To estimate the uptake of radiocesium (¹³⁷Cs) by tea plant roots, 1-year-old rooted tea cuttings (Camellia sinensis L. cv. Yabukita) at the time of bud opening were cultivated hydroponically for 27 days in pots containing nutrient solutions with or without ¹³⁷CsCl (600 Bq mL^-1). Total ¹³⁷Cs radioactivity of whole tea plants were 6.1 kBq g^-1 dry weight. The plant/solution ¹³⁷Cs transfer factors of different tissues were in the range of 2.6 (in mature leaves) to 28.2 mL g^-1 dry weight (in roots), which were lower than those reported in wheat and spinach. In total, 69% of ¹³⁷Cs remained in roots and 31% was transported from roots to shoots. The results indicated that ¹³⁷Cs was preferentially translocated to new shoots, which are used for manufacturing tea, over mature leaves.