元谋干热河谷燥红土和变性土上植物叶片的元素含量及其重吸收效率

采用盆栽试验,研究元谋干热河谷燥红土和变性土上生长的植物叶片以及凋落叶营养元素含量,并分析养分重吸收效率对土壤类型与物种互作的响应.结果表明: 土壤类型对叶片N、P、Ca、Mg、Cu、Zn、Fe、N∶P以及凋落叶N、P、Mn、N∶P均有显著影响;燥红土植物叶片与凋落叶N、Mn含量和N∶P显著高于变性土,而燥红土植物叶片P、Ca、Mg、Fe、Cu、Zn和凋落叶P含量显著低于变性土.燥红土植物叶片N含量较变性土高34.8%,而P含量低40.0%;在叶片凋落时,N、P、K表现为重吸收,而其他元素呈富集状态.燥红土凋落叶Ca、Mg、Mn富集系数显著高于变性土.物种仅对叶片N含量有显著影响,物种与土壤交互作用对植物叶片和凋落叶元素含量影响不显著,表明各土壤类型对不同物种元素含量的影响方式较为一致.土壤类型对植物元素含量的影响可进一步作用于干热河谷植物凋落物分解、植物-土壤的养分反馈以及生物地球化学循环.

Element concentration in leaves and nutrient resorption efficiency on dry-red soil and vertisols in dry and hot valley in Yuanmou,China.

By performing a pot experiment, the study compared leaf and litter element concentration between the dry-red soil and vertisols, and analyzed the interactive effects of soil types and species on leaf nutrient concentration and nutrient resorption efficiency. The results showed that the soil type significantly affected the concentrations of N, P, Ca, Mg, Cu, Zn, Fe and N:P in leaves as well as the concentrations of N, P, Mn and N:P in leaf litters. Concentrations of N, Mn and N:P in leaves and litters derived from the dry-red soil were significantly higher than those from the vertisols. In contrast, concentrations of P, Ca, Mg, Fe, Cu and Zn in leaves and concentration of P in litters derived from the dry-red soil were significantly lower than those from the vertisols. Leaf N concentration was 34.8% higher, and leaf P concentration was 40.0% lower from the dry-red soil compared with those from the vertisols. N, P and K showed net resorption while the other elements showed accumulating patterns when leaf was senesced. Accumulation of Ca, Mg and Mn of senesced leaves was significantly higher on the dry-red soil than on the vertisols. Species identities only significantly affected leaf N concentration. Interactions of species and soil taxonomy significantly affected nutrient concentration neither in leaves nor in leaf litters, indicating that soil taxonomy influenced plant nutrient concentration in a similar way across multiple species. The influences of soil types on plant element concentration could have further effects on litter decomposition, plant-soil nutrient feedback and biogeochemical cycle in this dry and hot valley.