DHI-NTU Centre, Nanyang Environment & Water Research Institute, N1.2-B1-02, Nanyang Technological University, Singapore 639798, Singapore.
Chemosphere. 2013 Jan;90(4):1568-72. doi: 10.1016/j.chemosphere.2012.09.059. Epub 2012 Oct 15.
Uptake, accumulation and translocation of caffeine by Scirpus validus grown in hydroponic condition were investigated. The plants were cultivated in Hoagland's nutrient solution spiked with caffeine at concentrations of 0.5-2.0 mg L(-1). The effect of photodegradation on caffeine elimination was determined in dark controls and proved to be negligible. Removal of caffeine in mesocosms without plants showed however that biodegradation could account for about 15-19% of the caffeine lost from solutions after 3 and 7 d. Plant uptake played a significant role in caffeine elimination. Caffeine was detected in both roots and shoots of S. validus. Root concentrations of caffeine were 0.1-6.1 μg g(-1), while the concentrations for shoots were 6.4-13.7 μg g(-1). A significant (p<0.05) positive correlation between the concentration in the root and the initial concentrations in the nutrient solution was observed. The bioaccumulation factors (BAFs) of caffeine for roots ranged from 0.2 to 3.1, while BAFs for shoots ranged from 3.2 to 16.9. Translocation from roots to shoots was the major pathway of shoot accumulation. The fraction of caffeine in the roots as a percentage of the total caffeine mass in solution was limited to 0.2-4.4% throughout the whole experiment, while shoot uptake percentage ranged from 12% to 25% for caffeine at the initial concentration of 2.0 mg L(-1) to 50-62% for caffeine at the initial concentration of 0.5 mg L(-1). However, a marked decrease in the concentration of caffeine in the shoots between d-14 and d-21 suggests that caffeine may have been catabolized in the plant tissues subsequent to plant uptake and translocation.
采用水培的方法研究了香蒲在不同浓度（0.5-2.0mg/L）咖啡因胁迫下的吸收、积累和迁移。将植物种植在添加咖啡因的霍格兰培养液中，黑暗对照实验表明光照对咖啡因的光降解作用可以忽略不计。然而，在没有植物的中试系统中，去除咖啡因表明生物降解可能占 3d 和 7d 后溶液中咖啡因损失的 15-19%。植物的吸收在咖啡因的去除中起重要作用。香蒲的根和茎叶中均检测到咖啡因。根中咖啡因的浓度为 0.1-6.1μg/g，茎叶中为 6.4-13.7μg/g。在根中咖啡因浓度与初始培养液浓度之间存在显著的正相关关系（p<0.05）。根中的生物积累因子（BAFs）范围为 0.2-3.1，茎叶中的 BAFs 范围为 3.2-16.9。从根向茎叶的迁移是茎叶积累的主要途径。在整个实验过程中，根中咖啡因占溶液中总咖啡因质量的比例限制在 0.2-4.4%，而对于初始浓度为 2.0mg/L 的咖啡因，茎叶的吸收比例为 12%-25%，对于初始浓度为 0.5mg/L 的咖啡因，吸收比例为 50%-62%。然而，在第 14 天到第 21 天之间，茎叶中咖啡因的浓度明显下降，这表明咖啡因可能在植物吸收和迁移后被植物组织代谢。
