| 摘要: |
| 【目的】研究不同径级侧柏古树根系、土壤和微生物生物量碳（C）、氮（N）、磷（P）含量及其生态化学计量比的变化特征，探究根系-土壤-微生物系统的内稳性，为古树健康管理提供科学依据。【方法】以陕西省黄帝陵景区内5种径级（20~40,41~60,61~80,81~100和>100 cm）侧柏古树为研究对象，测定不同径级侧柏古树根系、土壤和微生物生物量C、N、P含量，计算根系、土壤和微生物生物量C、N、P生态化学计量比，并分析以上指标间的相关性及内稳性特征。【结果】（1）随着径级增大，侧柏古树根系有机碳（ROC）、根系全氮（RTN）含量及根系C∶P、N∶P均呈增加趋势，根系全磷（RTP）含量呈降低趋势，并当径级>80 cm时显著降低；根系C∶N无显著变化。随着径级的增大，土壤有机碳（SOC）、土壤全氮（STN）含量呈增大趋势，而土壤C∶P呈先减小后增加的趋势；土壤全磷（STP）含量呈先增加后减小的趋势，且在径级＞40 cm后基本达到动态平衡。不同径级侧柏古树间的土壤微生物生物量碳（MBC）含量有显著差异，而土壤微生物生物量氮和磷（MBN、MBP）含量无显著差异，MBC、MBN、MBP含量均随着径级的增大呈先增加后减小趋势，均在径级81~100 cm处达到最大值；随着径级的增大，MBN∶MBP显著下降，MBC∶MBN和MBC:MBP均无显著变化。（2）SOC与ROC、RTN、RTP以及MBP呈显著或极显著相关，STN与RTN呈显著正相关，STP与MBN、MBP呈显著正相关；土壤C∶N与土壤N∶P以及MBC∶MBP呈极显著相关，而土壤C∶P与土壤N∶P、根系N∶P和MBC∶MBN均呈显著正相关。（3）内稳态性特征分析结果显示，MBP属于敏感态指标，根系C∶P、MBC均属于弱敏感态指标。【结论】黄帝陵景区不同径级侧柏古树根系与土壤和微生物生物量群落间C、N、P含量及其生态化学计量比存在较大差异，侧柏生长受P限制作用明显，因此在黄帝陵景区侧柏古树健康管理过程中要注重P的供给，尤以大径级侧柏古树为主。 |
| 关键词: 侧柏古树 根系 微生物生物量 生态化学计量特征 内稳性特征 |
| DOI：10.13207/j.cnki.jnwafu.2025.04.008 |
| 分类号: |
| 基金项目:国家重点研发计划项目（2022YFF1300405） |
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| Ecological stoichiometric characteristics of roots,soil and microbial biomass of different diameter classes of ancient Platycladus orientalis |
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CAI Yijun, LI Yajing, LIU Jinliang, YIN Daihao, ZHAO Zhong
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College of Forestry,Northwest A&F University,Yangling,Shaanxi 712100,China
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| Abstract: |
| 【Objective】This study aimed to examine the differences of carbon (C),nitrogen (N),phosphorus (P) contents,and ecological stoichiometric characteristics of roots,soil and microbial biomass of different diameter classes of Platycladus orientalis ancient trees and to explore the internal stability of root-soil-microbial system,so as to provide scientific basis for the health management of ancient trees.【Method】The contents of C,N and P in roots,soil and microbial biomass of five different diameter classes (20-40,41-60,61-80,81-100 and >100 cm) of Platycladus orientalis ancient trees in the Huangdi Mausoleum,Shaanxi Province,were determined to analyze their stoichiometric characteristics,interrelationships and internal stability characteristics.【Result】(1) With the increase of diameter class,the contents of root organic carbon (ROC),root total nitrogen (RTN) contents and root C∶P,N∶P showed an increasing trend.In contrast,the content of root total phosphorus (RTP) content showed a decreasing trend,and significantly decreased when the diameter class was >80 cm.However,the root C∶N ratio had no significant change.With the increase of diameter class,soil organic carbon (SOC) and soil total nitrogen (STN) both increased,the soil C∶P ratio initially decreased and then increased,while soil total phosphorus (STP) content initially increased and then decreased,ultimately reaching a dynamic equilibrium when diameter class >40 cm.The contents of soil microbial biomass carbon (MBC) were significantly different among different diameter classes,whereas the contents of soil microbial biomass nitrogen (MBN) and phosphorus (MBP) did not show significant differences.The contents of MBC,MBN and MBP all initially increased and then decreased as the diameter class increased,and reached the maximum value at 81-100 cm diameter class.As the diameter class increased,the ratio of MBN∶MBP decreased significantly,while the ratios of MBC∶MBN and MBC∶MBP remained relatively unchanged.(2) SOC was significantly correlated with ROC,RTN,RTP and MBP,STN was significantly positively correlated with RTN,and STP was significantly positively correlated with MBN and MBP.Soil C∶N was significantly correlated with soil N∶P and MBC∶MBP,while soil C∶P was significantly positively correlated with soil N∶P,root N∶P and MBC∶MBN.(3) The results of homeostasis analysis showed that MBP was a sensitive state index,while root C∶P and MBC were weak sensitive state indexes.【Conclusion】The C,N and P contents,and stoichiometric ratios of the roots,soil and microbial communities of different diameter classes of Platycladus orientalis in the Huangdi Mausoleum scenic area exhibited significant differences,and the growth of Platycladus orientalis was evidently limited by P.Therefore,attention should be given to the supply of P in the health management process of the ancient trees of Platycladus orientalis in the Huangdi Mausoleum scenic area,particularly for those belonging to the larger diameter classes. |
| Key words: Platycladus orientalis ancient trees root system microbial biomass ecological stoichiometry characteristics internal stability characteristics |
