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草业学报 ›› 2023, Vol. 32 ›› Issue (9): 160-172.DOI: 10.11686/cyxb2022401

• 研究论文 • 上一篇    

氮添加和刈割条件下羊草光合-CO2响应过程及模型比较研究

杨斯琪1(), 鲍雅静1(), 叶佳琦1,2, 吴帅1, 张萌1, 徐梦冉1, 赵钰1, 吕晓涛3, 韩兴国4,5   

  1. 1.大连民族大学环境与资源学院,辽宁 大连 116600
    2.内蒙古大学生态与环境学院,内蒙古 呼和浩特 010021
    3.中国科学院沈阳应用生态研究所额尔古纳森林草原过渡带生态系统研究站,辽宁 沈阳 110016
    4.中国科学院植物研究所植被与环境变化国家重点实验室,北京 100093
    5.中国科学院大学,北京 100049
  • 收稿日期:2022-10-07 修回日期:2022-11-30 出版日期:2023-09-20 发布日期:2023-07-12
  • 通讯作者: 鲍雅静
  • 作者简介:E-mail: byj@dlnu.edu.cn
    杨斯琪(1999-),女,河北承德人,在读硕士。E-mail: 3527388037@qq.com
  • 基金资助:
    国家自然科学基金项目(31971464);辽宁省创新人才支持计划项目(辽教函[2020]389)

Comparison of photosynthetic-CO2 response process and models of Leymus chinensis under differing nitrogen addition and mowing conditions

Si-qi YANG1(), Ya-jing BAO1(), Jia-qi YE1,2, Shuai WU1, Meng ZHANG1, Meng-ran XU1, Yu ZHAO1, Xiao-tao LYU3, Xing-guo HAN4,5   

  1. 1.College of Environment and Bioresources,Dalian Minzu University,Dalian 116600,China
    2.School of Ecology and Environment,Inner Mongolia University,Hohhot 010021,China
    3.Erguna Forest-Steppe Ecotone Research Station,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China
    4.State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China
    5.University of Chinese Academy of Sciences,Beijing 100049,China
  • Received:2022-10-07 Revised:2022-11-30 Online:2023-09-20 Published:2023-07-12
  • Contact: Ya-jing BAO

摘要:

草原植物光合作用受氮添加和刈割等草原管理措施的影响。依托内蒙古草甸草原的氮添加(0、2、5、10、20和50 g N·m-2·a-1)和刈割(刈割和非刈割)交互处理的野外控制试验,测定其优势物种羊草的光合-CO2响应过程。探究直角双曲线模型、非直角双曲线模型、直角双曲线修正模型和Michaelis-Menten模型对叶片光合-CO2响应曲线的拟合效果,以及光合特性对氮添加和刈割的响应。结果表明:非直角双曲线模型拟合的初始羧化效率和光呼吸速率最接近实测值;直角双曲线修正模型对CO2饱和点、CO2补偿点和最大净光合速率的拟合效果最好;直角双曲线修正模型的拟合优度最高;适度氮添加能提高羊草净光合速率、水分利用效率、最大净光合速率、初始羧化效率和CO2饱和点并降低CO2补偿点,提升羊草对CO2的利用效率;随CO2浓度的升高,氮添加浓度为20 g N·m-2·a-1并刈割的羊草净光合速率增幅较大,具有较高的最大净光合速率、CO2饱和点、水分利用效率和较低的CO2补偿点。综上,非直角双曲线模型和直角双曲线修正模型较适用于氮添加和刈割条件下羊草的CO2响应曲线拟合,在内蒙古草原施氮20 g N·m-2·a-1并刈割最有助于提高羊草光合能力,有利于增大生态系统固碳量。

关键词: 羊草, 氮添加, 刈割, 光合-CO2响应曲线, 拟合模型

Abstract:

Photosynthesis of plants is affected by grassland management practices such as nitrogen addition and mowing. In this research, the photosynthetic-CO2 response process of the dominant species, Leymus chinensis, was determined in a controlled field experiment exploring the interaction between nitrogen addition (0, 2, 5, 10, 20 and 50 g N·m-2·yr-1) and mowing (mown and unmown) in an Inner Mongolian meadow steppe. Leaf photosynthetic-CO2 response curves were fitted using a rectangular hyperbolic model, a non-rectangular hyperbolic model, a modified rectangular hyperbolic model and a Michaelis-Menten model in order to define photosynthetic trait responses of L. chinensis to nitrogen addition and mowing. It was found that the initial carboxylation efficiency and photorespiration rate of the non-rectangular hyperbolic model were closest to the measured values. The modified rectangular hyperbola model provided the best fit for CO2 saturation point, CO2 compensation point and maximum net photosynthetic rate, and the modified rectangular hyperbolic model the highest goodness of fit. Moderate nitrogen addition increased the net photosynthetic rate, water use efficiency, maximum net photosynthetic rate, initial carboxylation efficiency and CO2 saturation point, and decreased the CO2 compensation point, and thereby improved the CO2 use efficiency of L. chinensis. With the increase of CO2 concentration, the net photosynthetic rate of L. chinensis with nitrogen concentration of 20 g N·m-2·yr-1 with mowing increased, and higher maximum net photosynthetic rate, CO2 saturation point and water use efficiency was observed, together with a lower CO2 compensation point. In conclusion, the non-rectangular hyperbolic model and the modified rectangular hyperbolic model were more suitable for fitting L. chinensis CO2 response curves defining responses to nitrogen addition and mowing. In this experiment conducted on an Inner Mongolian steppe, the photosynthetic capacity of L. chinensis was most efficiently increased by applying 20 g N·m-2·yr-1 with mowing. This treatment combination is beneficial to carbon sequestration of the grassland ecosystem.

Key words: Leymus chinensis, nitrogen addition, mowing, photosynthetic-CO2 response curve, fitting model