| 摘要: |
| 【目的】研究氮对轻木（Ochroma pyramidale）人工林生长及C、N、P化学计量特征的影响，为轻木人工林的栽培提供理论依据。【方法】以1.5年生轻木为材料，采用随机区组设计，分别设置不施氮（N0）、50 kg/hm2尿素（N1）、50 kg/hm2缓释氮肥（PCU1）、100 kg/hm2尿素（N2）、100 kg/hm2缓释氮肥（PCU2）5个处理，测定不同处理轻木树高、胸径以及叶、枝和根的C、Ｎ、Ｐ含量，计算各器官C/N、N/P和C/P，最后对轻木人工林生长和C、N、P含量及化学计量比进行了表型可塑性分析和主成分分析。【结果】与N0处理相比，N1、N2、PCU1和PCU2处理树高和胸径均显著增加，其中N2处理的树高和胸径均最高。与N0处理相比，各施氮处理轻木叶、枝、根的C含量总体无显著变化；轻木叶、枝、根的N含量明显增加，总体以N2和PCU2处理较高；P含量在叶中呈下降趋势，在枝和根中总体呈升高趋势。与N0处理相比，各施氮处理轻木叶、枝、根C/N均下降；C/P在叶和根中总体表现为升高，在枝中表现为下降；N/P在叶和根中表现为升高，在枝中则有升有降。不同处理轻木生长和C、N、P含量及化学计量比特征的表型可塑性指数为0.06~0.57，其中根N、根C/N、根N/P、叶N、叶N/P的表型可塑性指数均较大，根C、枝C及叶C的表型可塑性指数较小。主成分分析结果显示，前两个主成分的累计方差贡献率为 54.3%，在主成分1中，叶N/P、根N、叶N及枝P的影响较大；在主成分2中，根P、叶C/P、枝C/P、叶C/N及根C/N、根C/P的影响较大。【结论】氮对轻木人工林生长及各器官C、N、P化学计量特征有明显的影响。施用氮肥不仅减缓了N元素对轻木生长的限制，而且影响了C、N、P在各器官中的分布。在以后轻木人工林的栽培中，在施用氮肥的基础上应适量补充磷肥。 |
| 关键词: 轻木人工林 氮添加 碳氮磷化学计量比 树高 胸径 |
| DOI：DOI:10.13207/j.cnki.jnwafu.2025.06.005 |
| 分类号: |
| 基金项目:国家自然科学基金项目（32071688） |
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| Effects of nitrogen on the growth and C,N and P stoichiometric characteristics of Ochroma pyramidale plantations |
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WEN Chengjing1, WU Junwen1, LIU Yuanxi1, CHEN Gang1, LI Zhiqi1, DUAN Guihe1, DU Guanben2, LIANG Wen3
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1.College of Forestry,Southwest Forestry University,Kunming，Yunnan 650224,China;2.College of Materials and Chemical Engineering,Southwest Forestry University,Kunming，Yunnan 650224,China;3.Jinghong Jinghong Farm Co.,LTD.,Xishuangbanna,Yunnan 666303,China
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| Abstract: |
| 【Objective】The study aimed to explore the effects of nitrogen on the growth of Ochroma pyramidale plantations and the stoichiometric characteristics of C,N and P so as to provide a theoretical basis for the cultivation of O.pyramidale plantations.【Method】1.5 years old O.pyramidale plants were selected and treated with no nitrogen (N0),50 kg/hm2 urea (N1),50 kg/hm2 slow-release nitrogen fertilizer (PCU1),100 kg/hm2 urea (N2) and 100 kg/hm2 slow-release nitrogen fertilizer (PCU2) in a randomized block design.The contents of C,N and P in leaves,branches and roots were measured,and the C/N,N/P and C/P ratios in each organ were calculated.Finally,phenotypic plasticity analysis and principal component analysis were conducted on the growth parameters,C,N and P contents and stoichiometric ratios of the plantations.【Result】Compared with N0 treatment,the tree height and DBH (diameter at breast height) of the N1,N2,PCU1 and PCU2 treatments were significantly increased,with the N2 treatment showing the highest tree height and DBH.Compared with N0 treatment,there was no significant change in C content in leaves,branches and roots.However,the N content of leaves,branches and roots of O.pyramidale increased significantly,with higher N content observed under the N2 and PCU2 treatments.P content decreased in leaves,but increased in branches and roots.Compared with the N0 treatment,the C/N ratio decreased in the leaves,branches and roots of O.pyramidale treated with nitrogen.The C/P ratio increased in leaves and roots,but decreased in branches.The N/P ratio increased in leaves and roots;however,in branches,it either increased or decreased.The phenotypic plasticity indexes of growth,C,N and P contents and stoichiometric ratios under different treatments ranged from 0.06 to 0.57,in which the phenotypic plasticity indexes of root N,root C/N,root N/P,leaf N and leaf N/P were higher,while the phenotypic plasticity indexes of root C,branch C and leaf C were lower.The results of the principal component analysis showed that the cumulative variance contribution rate of the first two principal components was 54.3%.Principal component 1 was strongly influenced by leaf N/P,root N,leaf N,and branch P.Principal component 2 was significantly affected by root P,leaf C/P,branch C/P,leaf C/N,root C/N,and root C/P.【Conclusion】Nitrogen had significant effects on the growth of O.pyramidale plantations and the stoichiometric characteristics of C,N and P in various organs.The application of nitrogen fertilizer not only reduced the restriction of N element on the growth of O.pyramidale,but also affected the distribution of C,N and P in various organs.In the future cultivation of O.pyramidale plantation,phosphorus fertilizer should be added in addition to nitrogen fertilizer. |
| Key words: Ochroma pyramidale plantations nitrogen addition C,N and P stoichiometric ratio height of the tree diameter at breast height |
