Microbeam analysis of Ca exchange and uptake in the fine roots of spruce: influence of pH and aluminum

摘要: A novel stable isotope labelling procedure for microbeam analysis was developed to monitor exchange and uptake of nutrients, primarily Mg, K Ca, by root tips at the cellular level. Initially samples were analysed from 2-year-old spruce trees, originating both a nursery polluted forest site, (1) cortex cell wall accessibility nutrient binding properties, (2) influence low pH elevated aluminum concentrations on Ca walls, (3) long-range transport into secondary xylem, proximal labelled tip. In control plants, is localized mainly in apoplast cortex. Exchange K, primary xylem with label incubation solutions almost completed equilibration within 30 min. we could detect minute amounts after min, as major fraction 48 h. This indicates that can be used study ion-exchange properties transport. Slight acidification media 4.5 reduced walls slightly, but extreme value 2.3 41%. combination increased free 83%. preliminary attempt analyse capability root-tip pollution affected exposed fine roots an acidified site showing typical levels Mg cortical Ca-enriched media. Under these conditions content doubled upon 4.7, reaching 40% total capacity our nursey plants.