W. K. Kellogg Biological Station, Michigan State University, Hickory Corners, Michigan 49060, and Center for Electron Optics, Department of Botany and Plant Pathology, and Pesticide Research Center, Michigan State University, East Lansing, Michigan 48824.
Appl Environ Microbiol. 1990 Sep;56(9):2882-90. doi: 10.1128/aem.56.9.2882-2890.1990.
We report a direct comparison of phosphate uptake by adnate and loosely attached microalgae in an intact biofilm matrix, with resolution at the level of individual cells. Track scanning electron microscope autoradiography enabled assay of [P]phosphate uptake from the overlying water by adnate algae left undisturbed on mature leaves of the macrophyte Potamogeton illinoensis or on artificial plant mimics. The epiphyte communities developed in either phosphate-poor or moderately phosphate-enriched water, and they were assayed on both natural and artificial plants. All adnate taxa examined from both natural and artificial plants in both habitats took up significantly less radiolabel when assayed beneath the overlying matrix than when they were exposed to the water upon removal of the overstory material. Track scanning electron microscope autoradiography and track light microscope autoradiography were intercalibrated to enable comparison of [P]phosphate uptake by adnate and loosely attached components of the epiphyte matrix. Loosely attached cells on substrata from both habitats took up significantly more radiolabel than did underlying adnate cells, indicating that access to phosphate supplies from the water depended on the position of microbial cells in the matrix. In this short-term assay, the adnate microalgae were relatively isolated from the water column nutrient source.
我们报告了在完整生物膜基质中，附着和松散附着的微藻对磷酸盐的吸收的直接比较，分辨率达到单个细胞的水平。追踪扫描电子显微镜放射自显影技术能够测定附着藻类从覆盖水层中吸收[P]磷酸盐，这些藻类附着在大型植物菹草的成熟叶片上或人工植物模拟物上，不受干扰。在贫磷或中度富磷水中形成的附生生物群落，在天然和人工植物上进行了测定。在两种生境中，从天然和人工植物上所有被检测的附着类群，当在覆盖基质下进行测定时，比在去除上层物质后暴露在水中时吸收的放射性标记物明显减少。追踪扫描电子显微镜放射自显影术和追踪光学显微镜放射自显影术相互校准，以比较附着和松散附着的附生生物基质成分对[P]磷酸盐的吸收。来自两种生境的基质上的松散附着细胞吸收的放射性标记物明显多于下面的附着细胞，表明从水中获取磷酸盐供应取决于微生物细胞在基质中的位置。在这个短期测定中，附着的微藻与水柱营养源相对隔离。
