Uptake, Accumulation, Translocation, and Subcellular Distribution of Perchlorate in Tea (Camellia sinensis L.) Plants

Perchlorate, emerging pollution with thyroid toxicity, has a high detection rate in fresh tea leaves. What needs attention is that the uptake characteristic is insufficiently understood. Herein, the uptake, accumulation, and translocation of perchlorate in a tea plant-hydroponic solution system were investigated, of which the mechanism was further lucubrated by subcellular distribution. The perchlorate concentration in tea tissues is ramped up along with the increase in the exposure level and time. The bioaccumulation factor of tea tissues followed the rank: mature leaves > tender leaves > roots. After the seedlings have been transplanted to a perchlorate-free solution, the perchlorate in mature leaves is reduced significantly, accompanied by a progressive increase in perchlorate in new shoots and solutions. The cell-soluble fractions are the major reservoir of perchlorate both for roots (>59%) and leaves (>76%), which precisely explained the translocation within the tea plant-hydroponic solution system. These results not only illuminate the uptake characteristic in tea plants but also improve the understanding of the behavior of perchlorate in higher plants.