贵州黄壤地区植物营养元素来源的Sr同位素示踪

Strontium isotopes as a tracer of plant nutrition element source in yellow soil region of Guizhou Province

为研究植物营养元素来源，对贵州龙里地区黄壤上生长的12种主要植物的部分营养元素含量及Sr同位素特征进行了分析。结果表明：喀斯特地区黄壤上的植物具有高钙含量，营养元素含量由高到低排序为Ca〉K〉Mg；研究区植物的Ca、K、Sr平均含量均高出报道的陆生植物的平均含量，但比贵州地区同样以灰岩为母质发育而来的石灰土上生长的植物低；植物样品的^87Sr／^86Sr同位素比值变化范围在0．70856～0．71145之间。基于锶同位素组成的端员模式计算结果表明，除了苔藓、石松的营养元素主要来源于大气输入外，其他植物的营养元素主要来源于土壤风化。

The strontium isotopic compositions and nutrition element concentrations of 12 plant species collected from yellow soil region in Guizhou Province of China were measured to investigate the source of plant nutrition elements. The results show that the plants growing in yellow soils of karstic areas have the characteristic of high concentration of Ca. The concentrations of nutrient elements were Ca 〉 K 〉 Mg. The mean concentrations of Ca, K and Sr in this region were higher than that of other terraneous plants in the world, but lower than that of the plants which grow in limestone soils from other karstic areas of Guizhou Province. The range of s7 SdS6 Sr ratios was from 0.708 56 to 0.711 45. Based on end-member models of s7 SdS6 Sr isotopes, the results indicate that the nutrient elements present in plants are mainly derived from soil weathering except for Lycopodium cernuum and Moss.