贵州中部喀斯特山地三种优势灌木养分分布

选择贵州喀斯特山区广泛分布的灌木林和灌草丛生态系统，探讨了三种优势灌木养分分布格局及其与土壤的关系。结果表明：（1）三种优势灌木叶片和果实的氮和钾元素含量高于茎干和根系，果实和茎干的磷含量比其他器官高，而钙镁主要集中在茎干和叶片。（2）在灌草丛中，三种灌木根系和茎干的N：P之间差异显著且变异很大，而在灌木林中，三种灌木根系的N：P比值变异较大，但它们之间没有差异。（3）根际有效态养分含量与叶片养分含量呈正相关关系，叶片磷与根际有效态磷显著正相关

Distribution patterns of main nutrients in three dominant shrubs in Karst mountainous areas in central Guizhou, China

The nutrient distribution patterns of three dominant shrubs and the relationships between plants and soils have been ex-mined in the shrubland and the shrub-and-grassland, which have been extensively distributed in mountainous area in Guihzou, China. The results showed that: (1) The N and K concentrations in leaves and fruits were significantly higher than that in stems and roots of three dominant shrubs. The P concentrations in fruits were markedly higher than that in the other organs. The Ca and Mg concentra-tions in leaves and stems were higher than that in the other organs. (2) In the shrub-and-grassland, there were significant differences in N:P ratios in stems and roots between three dominant shrubs, and the N:P ratios varied extensively among the three shrubs. In the shrubland, the N:P ratios varied extensively among the three shrubs. (3) The P concentrations were significantly related to available P contents in rhizospheric soils.The results indicated that the P would limit plants' growth and finally influence the biogeochemistry characteristics of the Karst ecosystems.