中国天然油松林主要物种根-叶功能性状时空动态及其对模拟氮沉降的响应

The adjustment and trade-offs among plant functional traits is an important way for plants to respond and adapt to the changing environment. The studies of plant functional traits may help us to predict the influence of global changes (e.g. climate change and atmospheric nitrogen deposition) on the structures and functions of terrestrial ecosystems. However, few studies have focused on one special species or community. The natural Pinus tabulaeformis forest is unique to China. In this study, we try to explore the spatial-temporal dynamics of leaf-root functional traits of the common species, especially P. tabulaeformis, and their response to simulated nitrogen deposition. In practice, we will take a series of ways to carry out this study, such as the dynamic investigations of the plant traits in fixed plots in natural P. tabulaeformis forest, Shanxi Taiyue Mountain, the transect investigation of natural P. tabulaeformis forests, and the long-term field-controlled experiment of simulated atmospheric nitrogen deposition in the natural P. tabulaeformis forest, Shanxi Taiyue Mountain. A series of plant traits (e.g. leaf morphological traits, fine root morphological traits, leaf stomatal traits, leaf anatomical traits, multi-element contents in leaves and fine roots) will be considered in this large-scale study. We will focus on the spatial-temporal dynamics of leaf traits and fine root traits, the co-varying of leaf traits and fine root traits, the main influencing factors, and how plant traits of different organs responding to simulated nitrogen deposition. We also try to explore how to scale up from the plant traits measured at the organ or individual level to the functions of natural plant community (e.g. gross primary productivity, water use efficiency, and others). This study will help us to understand and predict the response and adaptation mechanisms of plant traits of P. tabulaeformis and common species, and help us to make the effective policy for the protection and management of natural P. tabulaeformis forests under the scenarios of global change in the future.

植物功能性状的调整与最优化组合是植物对外界环境变化响应与适应的重要方式，其研究结果可为揭示全球变化对陆地生态系统结构和功能的影响提供重要理论基础。但真正围绕特定优势物种（或群落）开展的系统性研究较少。本项目拟以中国特有的天然油松林为对象，采用原位动态观测（太岳山森林生态系统定位站天然油松林固定监测样地）+天然油松林样带调查+天然油松林野外氮添加控制实验相结合的技术途径，在大尺度的研究中引入叶-根形态性状、叶片气孔性状、叶片解剖性状和多元素性状相结合的全面指标体系，重点研究样带尺度上和氮添加条件下天然油松林优势种油松及常见根-叶性状关联性、时-空动态、主要影响因素及其对氮添加的响应与适应机制，并探索解决如何将器官(个体)水平的性状与自然群落功能建立联系这一难点和热点问题。本项目不仅可促进植物性状研究领域的发展，还将为全球变化情景下制定天然油松林适应性管理策略提供重要的科技支撑。

植物功能性状是科学家揭示植物对环境变化响应与适应机制的重要途径，也是探讨未来全球变化（气候变化和氮沉降等）对陆地生态系统结构和功能影响的技术途径。本项目以太岳山森林生态系统定位站天然油松林固定样地、模拟氮沉降样地和天然油松林调查样带为研究对象，通过测量植物叶-根形态性状、元素含量、气孔性状等，探讨天然油松林主要物种根-叶性状关联性、时空动态及其对模拟氮沉降的响应。研究结论为科学地预测中国天然油松林对未来气候变化的响应与适应提供理论依据，为模型优化提供重要参数。.项目主要研究进展与成果包括：1）在氮添加下乔木叶片元素含量表现出稳定的化学计量响应；叶绿素含量显著增加以维持光合作用。灌木和草本植物叶片元素含量在高氮处理下表现出较高的化学计量响应。2）氮添加影响灌木和草本植物对结构器官的养分分配策略，而不影响乔木叶片与结构器官间的养分分配策略。3）在氮添加下，乔木更倾向于改变结构器官间P的分配策略，灌木倾向于改变对叶-枝P的分配策略；在结构器官间，氮添加加速对枝N和P含量的分配。上述结果对于预测植物养分分配策略对气候变化的响应提供理论支撑。4）植物叶和根化学计量特征随环境变化显著。总体上，乔木、灌木、草本植物的叶氮、碳、磷含量均随温度和降水量增加呈显著降低趋势。乔木、灌木根氮、磷含量随温度和降水量增加呈显著升高趋势。针叶树种和阔叶树种的叶元素含量随温度的升高呈显著降低趋势，细根磷含量、粗根磷含量呈显著升高趋势。5）天然油松林内不同生活型植物地上性状和地下性状之间协同作用较为显著，植物地上性状和地下性状之间存在权衡作用，这说明植物可以通过权衡以及协同作用适应环境条件的变化。.通过执行本项目，项目组共发表了 SCI 论文3 篇（第一标注3篇）、卓越期刊论文3篇（第一标注2篇）， CSCD 论文 2 篇（第一标注 2 篇，含1篇接收）。其中，部分论文发表在国际相关学科的主流期刊，如《Ecological Indicators》、《Journal of Forestry Research》、生态学报等。