基于氢氧稳定同位素的兰州南山绿化植物种选择——以锦鸡儿为例

Selection of greening plant species in the South Mountains of Lanzhou based on hydrogen and oxygen stable isotopes:A case study of Caragana

确定植物种的生态恢复适用性对绿化物种选择具有重要意义。本研究基于氢氧稳定同位素技术,以兰州市南山相似生境下狭叶锦鸡儿(Caragana stenophylla)和柠条锦鸡儿(C.korshinskii)为对象,采用直接对比法和贝叶斯混合模型(MixSIAR)对生长季两种锦鸡儿的水分来源差异进行定性和定量分析。结果表明:两种锦鸡儿有多个吸水层,是非单一水源植物,生长季狭叶锦鸡儿主要吸水层位具有月份差异性,而柠条锦鸡儿除了9月,其他月份主要水源均来自中深层(70~130 cm),贡献率达80%以上;降水发生后,狭叶锦鸡儿会转为利用表层(0~30 cm)土壤水,柠条锦鸡儿对降水响应不敏感;柠条锦鸡儿的主要吸水层位较为稳定,面对干旱胁迫时狭叶锦鸡儿能转换主要吸水层,具更灵活的吸水方式,干旱适应性优于柠条锦鸡儿,作为干旱区的绿化物种优势更为突出。

The ecological restoration applicability of plant species is of great significance to the selection of greening species. Based on hydrogen and oxygen stable isotope technique, we qualitatively analyzed the differences of water sources in growing season between two Caragana species(C. stenophylla and C. korshinskii) in similar habitats in the South Mountains of Lanzhou by using direct comparison method and Bayesian mixing models(MixSIAR). The results showed that the two species of Caragana have multiple water-absorbing layers and are non-single water source plants. The main water absorbing layer of C. stenophylla varied across different months in growing season. Except for September, the main water source of C. korshinskii was the medium-deep aquifers(70-130 cm), which contributed to more than 80%. C. stenophylla preferred to use surface soil water(0-30 cm) after rainfall, but C. korshinskii was not sensitive to rainfall. The main water absorbing layer of C. korshinskii was relatively stable. C. stenophylla can change the main absorbent layer in response to drought stress, indicating a more flexible strategy and strong ability to adapt to drought. Therefore, C. stenophylla has better applicability for ecological restoration.