摘要:不同根序的植物细根具有形态、结构和生理上的差异，基于根序的细根生理生态研究是当前生态学领域研究的重要组成部分。对不同生活型树种不同根序细根的研究可以为森林生态系统的地下细根养分策略提供理论依据。研究结果发现：（1）除了落叶树种P含量和N：P之外，两个生活型树种细根C、N和P含量与化学计量比在不同根序间均具有显著差异（P<0.05）；两者细根C含量、C：N和C：P随根序增加而升高，而N和P含量随根序增加而降低。（2）常绿与落叶树种C、N、P养分含量中C的变异系数最低，且两个生活型树种细根N、P含量的变异系数基本都随根序增加而变大。（3）常绿树种细根的N、P含量均显著低于落叶树种，但C：N和C：P都显著高于落叶树种，C含量和N：P无显著差异。（4）常绿与落叶树种细根养分（碳、氮和磷）异速关系在各个根序之间都存在共同斜率；常绿树种细根N和P含量存在等速生长关系，但落叶树种细根存在P含量增速大于N含量的异速生长关系（指数：α>1）。结论：随根序增加，常绿与落叶树种的细根具有相似的养分变化策略，N、P养分含量在低阶细根中的变异性更小。落叶树种细根生长受到缺P的影响大于常绿树种。落叶树种细根比常绿树种更高的N、P含量和更低C：N和C：P以及常绿与落叶树种细根N、P养分的异速生长关系差异说明落叶树种细根更倾向于采取快速的资源获取策略。



Abstract:The fine roots of different orders have morphological, structural and physiological differences. The study of fine root physiological ecology based on root order is an important part of current ecological research. Research on different root-order fine roots of different life-type trees can provide a theoretical basis for the underground fine root nutrient strategy of forest ecosystem. The results of this study showed that: (1) Except for the P content and N:P of deciduous trees, the content of C, N and P as well as their stoichiometric ratios in the fine roots of evergreen and deciduous species were significantly different in different root orders (P<0.05). The content of C, C:N, and C:P in fine roots increased with the increase of root order, while the content of N and P decreased with the increase of root order. (2) The content of C had the lowest coefficient of variation in the C, N, and P nutrient contents of evergreen and deciduous trees, and the coefficient of variation of N and P content in fine roots of two life-type trees increased with the increase of root order. (3) The N and P contents of fine roots of evergreen tree species were significantly lower than those of deciduous trees, but C:N and C:P were significantly higher than those of deciduous trees. The content of C and N:P were not significantly different between the evergreen and deciduous trees. (4) The allometric relationship of the fine root nutrient (C, N and P) of evergreen and deciduous trees had a common slope between different orders. The relationship of N and P in the fine roots of evergreen tree species was isometric, but the fine roots of deciduous tree species had an allometric growth relationship with the growth rate of P content greater than that of N(exponent: α>1). In conclusions, with the increase of root order, the fine roots of evergreen and deciduous trees had similar change strategies of nutrient. The N and P nutrient contents had less variability in low-order fine roots. The fine root growth of deciduous trees was more affected by P deficiency than that of evergreen species. The higher N, P content and lower C:N and C:P of deciduous tree species than that of the evergreen tree species as well as the allometric growth of N and P nutrients of the fine roots of evergreen and deciduous trees indicated that the fine roots of deciduous trees were more likely to adopt rapid resource acquisition strategies.





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