伊犁草原白喉乌头根和叶生态化学计量特征

Ecological stoichiometry characteristics of roots and leaves of Aconitum leucostomum in Yili grassland

摘要:

【目的】以伊犁草原分布的白喉乌头（Aconitum leucostomum）为对象，分析白喉乌头入侵前后的碳氮比（C∶N）、氮磷比（N∶P）和碳磷比（C∶P）的化学计量比，并明确白喉乌头根和叶中 C、N 和 P 元素的化学计量特征在不同月份的变化及其关联性。【方法】测定白喉乌头在不同月份和不同器官 C、 N 和 P 含量及化学计量比的变化，以及白喉乌头入侵前后土壤 C∶N、N∶P 和 C∶P 的化学计量特征变化， 并分析之间的相关关系。【结果】土壤 C∶N、N∶P 和 C∶P 的平均值在入侵土分别为 22. 947、4. 067、 91. 211；在未入侵土分别为 23. 029、4. 071、92. 345。可见，未入侵土的 C∶N、N∶P 和 C∶P 均高于入侵土 （P＞0. 05）。白喉乌头根的 C、N、P 含量的范围分别为 248. 08~337. 26、10. 20~13. 56、1. 35~1. 86 g/ kg，而叶片碳、氮、磷含量分别为 320. 23~446. 29、19. 20~36. 74、0. 95~3. 32 g/kg。C、N 和 P 元素在不同月份和不同器官中的分配也存在一定的差异，而且其含量均表现出叶＞根，体现出植物从地上至地下的养分含量呈下降的趋势。由相关性分析可知，白喉乌头根 C、N、P 与叶的 C、N、P 呈现正相关的关系，植物养分从体内进行传输，白喉乌头的根和叶对 C、N、P 的表现出一致性，为白喉乌头的稳定生长提供有利条件。根作为植物吸收养分和水分的重要器官，将所吸收的养分从地下部分运输到地上部分进而实现植物的正常生长发育，白喉乌头根的 C∶N 和 C∶P 与叶的 C∶P 和 N∶P 呈显著的正相关关系（P ＜0. 05），而 N 和 P 与 C∶N、N∶P 和 C∶P 呈负相关关系，从而表现出根和叶在养分利用方面的协同变化， 同时也说明 N 和 P 元素在白喉乌头生长阶段发挥着重要的作用。【结论】与未入侵的土壤相比较，入侵土壤铵态氮、有效磷和速效钾明显增加，说明入侵植物可能会造成土壤养分的变化。

Abstract:

【Objective】 Taking Aconitum leucostomum distributed in Yili grassland as the object，the stoichiomet- ric ratios of C∶N，N∶P and C∶P before and after the invasion of A. leucostomum were analyzed. The changes and cor- relations of the stoichiometric characteristics of C，N and P elements in roots and leaves of A. leucostomum in differ- ent months were also Investigated.【Method】 Mainly measure the characteristic changes of C，N and P content and stoichiometric ratio in different months and organs of A. leucostomum，as well as changes in soil C∶N，N∶P and C∶P stoichiometric characteristics before and after the invasion A. leucostomum，and analyze the correlation between them. 【Result】 The results showed that the average values of soil C∶N，N∶P and C∶P were 22. 947，4. 067 and 91. 211 re- spectively in the invaded soil；23. 029，4. 071 and 92. 345 in non-invaded soil respectively. It was found that the C∶ N，N∶P and C∶P of non-invaded soil were higher than those of invaded soil （P＞0. 05）. The contents of C，N and P in roots of A. leucostomum ranged from 248. 08~337. 26 g/kg，10. 20~13. 56 g/kg，and 1. 35 to 1. 86 g/kg，respec- tively，while the contents of C，N and P in leaves were 320. 23~446. 29 g/kg，19. 20~36. 74 g/kg，and 0. 95~3. 32 g/kg，respectively. The distribution of C，N and P varied in different months and different organs，and the N and P in the leaf were higher than those in the root. The results suggested that the nutrient content of plants decreased from above ground to underground. According to the correlation analysis，the root C，N and P of A. leucostomum had a positive correlation with the leaf C，N and P. Plant nutrients were transported from the body. The root and leaf of A. leucostomum had the same C，N and P，which provides favorable conditions for the stable growth of A. leucostomum. As an important organ for plants to absorb nutrients and water，the root transports the absorbed nutrients from the un- derground part to the aboveground part so as to achieve the normal growth and development of plants. C∶ N and C∶P of the root of A. leucostomum were significantly positively correlated with C∶P and N∶P of the leaf （P＜0. 05），while N and P were negatively correlated with C∶N，N∶P and C∶P，thus showing the synergistic changes of the root and leaf in nutrient utilization. The results also suggested that N and P elements may play an important role in the growth stage of A. leucostomum.【Conclusion】 Compared with the non-invaded soil，the ammonium nitrogen，available phos- phorus and available potassium in the invaded soil increased significantly，indicating that the invasive plants may cause changes in soil nutrients.