应用电子探针技术进行苗木根际元素分布研究

STUDIES ON ELEMENT DISTRIBUTION OF SEEDLING RHIZOSPHERE WITH ELECTRON MICROPROBE ANALYSIS

生长于不同土壤条件下的刺槐、湿地松的根土边界层上,营养元素的分布都有浓度梯度。Ca、Mg、K和P在根际的累积或亏缺的变动空间为25～400μm之间。土壤类型、施肥和树种特性对此范围均有影响。供试样品近根处都有一个Si、A1和Fe含量低的层次,明显地与土壤和根组织不同。据此判断,在苗木根土边界层中,粘胶层厚度在25～75μm范围内变动。

In the root-soil ecoboundary layers of black locust and slash pine growing under different soil conditions, there existed a concentration gradient of nutrient elements. The accumulation or deficit of Ca, Mg, K and P occurred in a distance of 25-400 μm from the root surface and was affected by soil types, fertilization and plant species. Mucilage layers found on the root surface were evidenced by low concentration of Si, Al and Fe within a range of 25-75 urn. It could be considered that the mucilage layer was an important part of the ecoboundary layer functioning as a passage of material exchange and energy flow between the root and soil.