喀斯特生态退化区土壤Ca和pH对药用草本植物的分布及P素利用效率的影响及机制

Current understanding about the impact of high calcium (Ca) and pH on low phosphorus (P) utilization in endemic plants of ecology-degraded Karst region is mainly derived from micro-scale site studies, but less information is aware about inherent mechanism at large scale. It is hard to fully explain the interference of soil chemical factors to the distribution of endemic plants in Karst regions. In the current project plan, ecology-degraded Karst regions in Guizhou Province, China, were chosen as the objective research area with comparison to the other region with much better ecological status. Therein, three endemic species of medicinal herbs were investigated and sampled for their growth, biomass, and Ca and P contents in shoot and root parts. Meanwhile, soil parameters of Ca and P contents and pH value were also investigated within the same plots of sampled plants. Both distribution patterns of plant and soil parameters were detected separately whose relationship with each other, however, was detected thereafter..Sampled plants were planted in pots placed in controlled environment to measure their foliar photosynthetic rate and gas exchange and P-uptake kinetics and foraging behavior in heterogeneous P patches by roots, which can help to determine the mechanism for P utilization in medicinal herbs distributed at large field scale. Data from this project plan would supply theoretical reference for the protocol of vegetation restoration of ecology-degraded Karst regions of China.

目前有关喀斯特生态退化区高钙（Ca）、高pH对植物磷（P）素利用效率影响的理解大多停留在样地水平层面，对于大尺度下植物响应机制方面的了解相对较少，因此尚无法确切解释土壤化学要素干扰乡土植物天然分布的原因。本项目拟以我国贵州省内已退化的喀斯特地区为研究区域，以生态环境相对较好的地区为对照区，以当地3个药用草本植物种类为对象，通过野外大尺度的样地调查得出土壤Ca、pH、P和植物指标的空间分布格局并分析二者间相关性，另通过室内控制试验的手段研究植物叶片的光合、气孔导度和根系的P素离子流动力学特征和异质性觅P行为，以此揭示宏观尺度上影响植物P素有效性的关键机制，为喀斯特地区退化生态系统中植被的恢复提供理论参考

明析生态退化对喀斯特药用草本植物 P 素利用的影响和主要机制。室内盆栽试验在贵州大学温室内开展，采用盆栽方法进行试验，以 3 种药用草本植物为材料。 采用2 因素 2 水平的因子设计开展 3 个品种的平行实验，将含有 P 离子的溶液按照试验设计添加入同质性或异质性的环境中，之后将 2 种浓度的含 Ca 溶液均匀的浇入整个花盆中。试验期间根据天气和温度情况每 1-2 天灌溉一次，每周进行 Ca和 P 离子添加一次。盆栽试验持续到 9 月末。收获时首先减去植株的地上部分，之后收获异质性环境中的供养区和对角区内的所有根系，从同质性环境中随机收集 2 个对角区内的所有根系。根系用于检测形态指标、干重和 Ca、 P 含量，部分全部用于检测形态指标、干重和 Ca、 P 含量。鬼针草根尖数在不同Ca、P环境中的变化范围在1321.23至3291.10范围内，在低Ca含量土壤环境中鬼针草根尖数（2086.08±1256.31）显著高于高Ca土壤环境中的水平（1690.74±653.06），而在高P含量土壤斑块中鬼针草根尖数（2636.45±2158.12）显著高于低P（1962.68±759.03）或无P的水平（1540.03±694.61）；蒲公英在低Ca环境中的高P素含量的土壤斑块中的根尖数显著多于其他斑块中水平，在低Ca、无P环境中根尖数最少；车前在低Ca环境中高量P素含量的土壤斑块中的根尖数显著高于其他处理水平，而在高Ca环境中无P斑块中的水平最低。P素含量的升高诱导植物分布更多的细根觅养响应行为，具体表现是形态增加并且根尖数增多。

内容获取失败，请点击重试