Crush J R, Briggs L R, Sprosen J M, Nichols S N
AgResearch, Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand.
Environ Toxicol. 2008 Apr;23(2):246-52. doi: 10.1002/tox.20331.
The effect of irrigation with lake water containing a variety of microcystins on accumulation of toxins, or toxin metabolites, and plant growth in ryegrass, clover, rape, and lettuce, was investigated in a glasshouse experiment. The plants were grown in sand culture and received either three or six applications of lake water, which was applied either directly to the sand surface or to the plant shoots. As determined by LC-MS, each plant received 170 mug of a mixture of 10 different microcystins per application. Microcystins in plant samples were extracted with 70% methanol and analyzed by Adda-specific ELISA. For the shoot application treatment, microcystins were not present at measurable levels in shoots of ryegrass or rape, but were present in lettuce [0.79 mg/kg dry weight (DW)] and clover (0.20 mg/kg DW). Total microcystin concentration in roots did not vary greatly depending on whether treatment water was applied directly to the sand, or reached the roots via run-off from the shoots. Microcystins in roots were highest in clover (1.45 mg/kg DW), intermediate in lettuce (0.68 mg/kg DW) and low in ryegrass (0.20 mg/kg DW), and rape (0.12 mg/kg DW). There was no evidence for root-to-shoot translocation of microcystins. Three applications of microcystins reduced shoot DW of ryegrass, rape and lettuce, and increased root DW of ryegrass and lettuce. Clover DW was not changed by treatment with microcystins. The results show that irrigation with water containing microcystins has the potential to move microcystins into farm animal and human food chains at concentrations that can exceed recommended tolerable limits.
在温室实验中，研究了用含有多种微囊藻毒素的湖水灌溉对黑麦草、三叶草、油菜和生菜中毒素或毒素代谢产物积累以及植物生长的影响。植物采用砂培法种植，接受三次或六次湖水灌溉，湖水直接浇灌在砂面或植株地上部分。通过液相色谱 - 质谱联用仪测定，每次灌溉每株植物接受170微克由10种不同微囊藻毒素组成的混合物。植物样品中的微囊藻毒素用70%甲醇提取，通过Adda特异性酶联免疫吸附测定法进行分析。对于地上部分浇灌处理，黑麦草或油菜的地上部分未检测到可测量水平的微囊藻毒素，但生菜（0.79毫克/千克干重）和三叶草（0.20毫克/千克干重）中存在微囊藻毒素。根部微囊藻毒素的总浓度并不因处理水是直接浇灌在砂上还是通过地上部分径流到达根部而有很大差异。根部微囊藻毒素含量在三叶草中最高（1.45毫克/千克干重），生菜中居中（0.68毫克/千克干重），黑麦草（0.20毫克/千克干重）和油菜（0.12毫克/千克干重）中较低。没有证据表明微囊藻毒素存在从根部向地上部分的转运。三次微囊藻毒素处理降低了黑麦草、油菜和生菜的地上部分干重，增加了黑麦草和生菜的根部干重。微囊藻毒素处理未改变三叶草的干重。结果表明，用含有微囊藻毒素的水灌溉有可能使微囊藻毒素以超过推荐耐受限度的浓度进入农场动物和人类食物链。
