除草剂扑草净和阿特拉津对海草与大型藻类的毒性比较

陆地径流等可引起海域中除草剂浓度升高, 从而威胁海洋大型植物——海草和大型藻类的生长。以叶绿素荧光为主要指标测定除草剂阿特拉津和扑草净的低、中、高(1、5和25 μg/L)浓度对4种常见海草:大叶藻(Zostera marina L.)、丛生大叶藻(Z. caespitosa M.)、矮大叶藻(Z. japonica Aschers. & Graebn.)、红须根虾形藻(Phyllospadix iwatensis M.)和2种常见大型藻类:孔石莼Ulva lactuca L.和海索面Nemalion helminthoides的光合抑制。结果显示, 低浓度1 μg/L的扑草净和5 μg/L的阿特拉津即对矮大叶藻、孔石莼和海索面产生了显著的光合抑制, 抑制率约而7.54%—12.97%; 大叶藻、丛生大叶藻和红须根虾形藻的扑草净和阿特拉津的显著作用浓度为5 μg/L, 在相同浓度下, 扑草净的光合抑制较阿特拉津更强, 同时, 矮大叶藻及两种大型藻类较其他3种海草成体对除草剂作用更为敏感。

COMPARISON OF THE HERBICIDE ATRAZINE AND PROMETRYN'S TOXICITY ON SEAGRASS AND SEAWEED

Herbicide that applied to agriculture can contaminate estuarine and costal ecosystems through overspray, ground-water leachate and runoff to impair the health of seagrass and seaweed. This study investigated the toxic effects of herbicide atrazine (1 μg/L, 5 μg/L and 25 μg/L) and prometryn based on the photosystem II (PSII) inhibition on four species of seagrass (Zostera marina,Z. caespitosa,Z. japonica andPhyllospadix iwatensis M.) and 2 species of sea-weed (Ulva lactuca L.,Nemalion helminthoides) in north China. Results showed that the maximum quantum yield ofZ. japonica.U. lactuca L.,N. helminthoides andZ. marina L seedlings depressed significantly at 1 μg/L prometryn and 5 μg/L atrazine after 72h exposure, andZ. marina,Z. caespitosa andP. iwatensis depressed at both 5 μg/L prometryn and atrazine. At the same concentration, prometryn showed higher toxicity than atrazine for all species.Z. japonica and the two seaweed were more sensitive to herbicide then others.