植物生态学报 ›› 2014, Vol. 38 ›› Issue (6): 640-652.DOI: 10.3724/SP.J.1258.2014.00060

• 综述 • 上一篇    下一篇

植物叶片最大羧化速率与叶氮含量关系的变异性

闫霜1,2,张黎2,*(),景元书1,何洪林2,于贵瑞2   

  1. 1南京信息工程大学应用气象学院, 南京 210044
    2中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室, CERN综合研究中心, 北京 100101
  • 收稿日期:2013-12-19 接受日期:2014-03-27 出版日期:2014-12-19 发布日期:2014-06-10
  • 通讯作者: 张黎
  • 基金资助:
    基金项目 国家自然科学基金(31000235);国家重点基础研究发展计划(2010CB833503);国家自然科学基金重大项目(31290221)

Variations in the relationship between maximum leaf carboxylation rate and leaf nitrogen concentration

YAN Shuang1,2,ZHANG Li2,*(),JING Yuan-Shu1,HE Hong-Lin2,YU Gui-Rui2   

  1. 1College of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China
    2Synthesis Research Center of Chinese Ecosystem Research Network, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
  • Received:2013-12-19 Accepted:2014-03-27 Online:2014-12-19 Published:2014-06-10
  • Contact: ZHANG Li

摘要:

叶片最大羧化速率是表征植物光合能力的关键参数, 受到光照、温度、水分、CO2浓度、叶片氮含量等多个要素的控制。准确地模拟植物叶片最大羧化速率对环境因子的响应是预测未来植被生产力和碳循环过程的前提。目前大多数陆地碳循环过程模型以Farqhuar光合作用模型为基础模拟植物的光合作用, 关于植物叶片的最大羧化速率与叶氮含量关系的模拟方法却各不相同。该文汇总了1990-2013年国内外植物叶片光合速率观测研究文献中叶片最大羧化速率与叶氮含量的关系式及相关数据, 分析了叶片最大羧化速率与叶氮含量关系随不同植被功能型和时间的变化特征, 以及环境因子变化条件下最大羧化速率与叶氮含量关系的变化特征, 探讨了二者关系变异性的可能原因以及影响因子。结果表明: 1)不同功能型植物叶片的最大羧化速率和叶氮含量的关系存在较大差异, 二者线性关系式的斜率平均值变化范围为16.29-50.25 μmol CO2·g N-1·s-1。落叶植被叶片的最大羧化速率随叶氮含量的变化率和光合氮利用效率一般都高于常绿植被, 其变异主要源于植物的比叶重和叶片内部氮素分配的差异。2)叶片最大羧化速率随叶氮含量的变化存在季节和年际变异。在没有受到水分胁迫的年份中, 叶片最大羧化速率随叶氮含量变化的速率一般在春季或夏季最高, 其季节变异与比叶重和叶氮在Rubisco的分配比例的季节变化有关。受到干旱的影响, 叶片最大羧化速率随叶氮含量的变化率会升高。3)当大气CO2浓度增加时, 由于叶片中Rubisco含量的降低, 多年生针叶叶片最大羧化速率和叶氮关系斜率值会出现降低; 当供氮水平增加时, 叶片最大羧化速率和叶片氮含量均表现出增加趋势, 二者线性关系的斜率也相应增加。在此基础上, 该文指出在模拟叶片最大羧化速率与叶氮含量的关系时, 应考虑叶片比叶重和叶氮在Rubisco中的分配比例的季节变异、水分胁迫、大气CO2浓度和供氮水平变化对二者关系的影响。囿于数据的有限性, 今后应进一步加强多因子控制实验研究, 深入探讨叶片最大羧化速率与叶氮含量关系的变异性机理, 并获得更系统的观测数据, 以助生态系统过程模型的改进, 提高模型的模拟精度。

关键词: 叶片氮含量, 叶片最大羧化速率, 植物光合作用, 陆地碳循环模型

Abstract:

Aims Maximum leaf carboxylation rate is one of the key parameters determining the photosynthetic capacity of plants. It is affected by irradiance, temperature, moisture, atmospheric CO2 concentration, leaf nitrogen content, and some other factors. Accurate simulation of the responses of the maximum leaf carboxylation rate to varying environmental conditions is the premise for predicting the changes in vegetation productivity and carbon cycle in future environments. Most of the process-based terrestrial carbon cycle models use the Farqhuar photosynthesis model to simulate plant photosynthesis. However, the methods in simulating the relationship between maximum leaf carboxylation rate and leaf nitrogen content differ from each other.
Methods We collected data on maximum leaf carboxylation rate and leaf nitrogen content from literature published during 1990-2013, and analyzed the variations in the relationship between maximum leaf carboxylation rate at 25 ℃ (Vcmax,25) and area-based leaf nitrogen concentration (Na) across different plant functional types and seasons, and in responses to rising atmospheric CO2 and nitrogen supply. Moreover, we reviewed possible causes of those variations and the influencing factors.
Important findings The results showed that: 1) the relationship between Vcmax,25 and Na varied with plant functional types, and the average values of the slope ranged from 16.29 to 50.25 μmol CO2·g N-1·s-1. Deciduous trees generally showed a steeper slope and greater photosynthetic nitrogen use efficiency than evergreen trees due to the differences in leaf mass per area (LMA) and nitrogen allocation to Rubisco. 2) The relationship between Vcmax,25 and Na had seasonal and annual variations. In years without water stress, the highest value of the slope mostly occurred in spring or summer. A change of the slope was related to seasonal variations in LMA and nitrogen allocation to Rubisco. The slope increased in drought seasons or years. 3) The slope of the linear relationship between Vcmax,25 and Na for perennial needle leaf was reduced due to a decrease in Rubisco content in response to elevated CO2. The maximum leaf carboxylation rate, nitrogen content, and the slope of their linear relationship increased with increment of nitrogen application rate. On the basis of these analyses, we suggest that simulating the relationship between maximum leaf carboxylation and leaf nitrogen should consider seasonal variations in LMA and nitrogen allocation to Rubisco, the influences of water stress, atmospheric CO2 concentration, and nitrogen supply level. More multi-factor experimental studies are needed to further investigate the underlying mechanisms of the variations in the relationship between maximum leaf carboxylation rate and leaf nitrogen content, to obtain more observational data with systematic approaches, and thus to further improve ecosystem process-based models.

Key words: leaf nitrogen, maximum leaf carboxylation rate, photosynthesis, terrestrial carbon cycle model