塔克拉玛干沙漠腹地人工植被及土壤CNP的化学计量特征

The stoichiometric characteristics of C,N,P for artificial plants and soil in the hinterland of Taklimakan Desert

生态化学计量学是研究生态过程和生态作用中化学元素平衡的科学。极端环境中进行植物叶片与土壤中营养元素含量及变化研究,对于揭示植物对营养元素的需要和当地土壤的养分供给能力,以及植物对环境的适应与反馈能力具有十分重要的意义。以塔克拉玛干沙漠腹地塔中植物园生长良好的25种人工植被及其生境为研究对象,运用方差分析、相关分析综合研究植物叶片及土壤的化学计量特征及其相互关系。结果显示:塔克拉玛干沙漠腹地25种人工植被叶片C、N、P的平均含量分别为(386.7±46.6)、(24.7±8.1)和(1.8±0.78)mg/g;叶片C∶N、C∶P及N∶P分别为(17.5±6.7)、(249.2±102.8)、(15.0±5.6)。其中豆科植物N含量极显著高于非豆科植物(P<0.001)。不同生活型植物的C、N、P含量均存在显著差异,C、N、P含量在3种生活型的大小顺序为草本>灌木>乔木。C∶N和N∶P在不同生活型植物间不存在显著差异(P>0.05),而乔木和灌木的C∶P显著高于草本植物(P<0.05)。相关分析表明植物的叶片C∶N、C∶P都与相应的N、P含量呈现极显著负相关性(P<0.001),而叶片N含量与P含量的变化并不相关(P>0.05)。土壤C、N、P养分元素含量远低于全国的平均水平,尤其是N含量(<0.2 mg/g);土壤C与N存在着极显著的正相关关系(P<0.01),而C与P、N与P间的相关性并不显著(P>0.05)。以上研究结果表明,受极端环境的限制,塔克拉玛干沙漠人工植被植物对养分元素的利用效率显著低于全国陆地植物的平均水平,不同科和不同生活型功能群植物对环境的适应能力显著不同,表现出显著的养分适应策略差异性。

Ecological stoichiometry is the study of the balance of muhiple chemical elements in ecological interactions ; it is the important content and hotspot in ecology research.Ecological stoichiometry plays an important role in determining plants and ecosystem nutrient supply and demand and their balance.The content of plant chemical element at different organs is restricted by the environmental nutrient availability, especially by the restricted nutrient, and it also affected by plant growth form, the physical characteristics and life history, which is the result of environment and species phylogenesis development together. Study on the plants leaf nutrient content and its variance in extreme environment is important in revealing the plants nutrient requirement and soil nutrient supply capacity, it is also important in revealing the plants adaptability to environment.This study was conducted for 25 artificial plants which from different family and life form in thehinterland of Taklimakan Desert, using variance analysis and correlation analysis together to determine the stoichiometric characteristics and its relationship for plant leaf and soil.The results showed that the mean content of artificial plants leaf C, N, P were （ 386.7 ± 46.6）, （ 24.7 ± 8.1 ） and （ 1.8± 0.78 ） mg/g respectively in Taklimakan Desert, leaf N was significantly higher than those plants which were not desert plants. C ： N, C ： P were （ 17.5±6.7 ）, （ 249.2 ± 102.8 ） respectively, which were lower than the average of global land plants, and indicated that extreme environment restricted the use of nutrient elements for artificial desert plants. And 14〈N ：P〈 16 （15.0 ~5.6）, which indicated plants growth were restricted by N and P together in the study area.Also the N content for legume plants was greatly higher than non-legume plants indicating significant nitrogen fixation for legume plants.Great difference for leaf C, N, P content were presented in different life form plants were also obtained in this study, C, N and P content were also presented as herb〉shrub 〉tree. There was no difference for C ：N and N ：P between different life forms, while the C ：P for shrub and tree functional group were significantly higher than herb functional group.The correlation analysis indicated that leaf C ：N, C ：P were negatively correlated with N, P content significantly, while no correlation between leaf N and P.Soil nutrient content were significantly lower than other region, especially for soil N content （〈0.2 mg/g） , significantly positive correlation between soil C and N （P〈0.01）, and no correlation between soil C and P, N and P （P〉0.05）.In all, the above results documented that extreme environment of nutrient restricted area limited the plants＇ nutrients use efficiency, which may be the adaptive strategy for the artificial plants in extreme environments.Besides, different functional group had different adaptability to environment, and significantly nutrient adapt strategy diversity was presented in this study.