Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Sci Total Environ. 2009 Dec 20;408(2):425-30. doi: 10.1016/j.scitotenv.2009.09.035. Epub 2009 Oct 22.
Foliar leaching might be an important process in the biogeochemical cycle of elements, but the leaching behaviors of As remain unclear. This study examined As leaching from foliage of an As-hyperaccumulator, Pteris vittata L. in the field. Results indicated that substantial amounts of As can be leached from the foliage by precipitation. Arsenic concentrations in the foliar leachate ranged from 4.06 to 519 microgL(-1), and the percentages of As(III) with respect to total As in leachate ranged from 5% to 10%. A positive linear relationship existed between As concentrations of the foliar leachate and the amounts of As accumulated in the plant. The rate of As leaching from the leaves was accelerated by an increase of rainfall and time in a simulated precipitation experiment. Water-soluble As distributed within the cuticle and apoplast of the plant was speculated as the main source of the leached As. The As leaching is an important process of within-ecosystem As cycling in phytoremediation and it deserves further investigation.
叶片淋溶可能是元素生物地球化学循环中的一个重要过程，但砷的淋溶行为仍不清楚。本研究在野外条件下考察了砷超富集植物蜈蚣草叶片中的砷淋溶行为。结果表明，大量的砷可以通过沉淀从叶片中淋溶出来。叶浸提液中的砷浓度范围为 4.06-519 µgL(-1)，浸提液中砷（III）相对于总砷的百分比范围为 5%-10%。叶浸提液中砷浓度与植物中砷积累量之间存在正线性关系。在模拟降水实验中，随着降雨量和时间的增加，叶片中砷的淋溶速率加快。推测植物表皮和质外体中的水溶性砷是淋溶砷的主要来源。砷的淋溶是植物修复过程中生态系统内砷循环的一个重要过程，值得进一步研究。
