氮沉降和刈割条件下羊草光响应模型比较及响应特性  

Comparison of light response models and response characteristics of Leymus chinensis under nitrogen deposition and mowing conditions

作　　者：杨斯琪 鲍雅静 叶佳琦 吴帅 张萌 徐梦冉 赵钰 吕晓涛[3] 姜良超 韩兴国[4,5] YANG Siqi;BAO Yajing;YE Jiaqi;WU Shuai;ZHANG Meng;XU Mengran;ZHAO Yu;LÜXiaotao;JIANG Liangchao;HAN Xingguo(College of Environment and Bioresources,Dalian Minzu University,Dalian 116600,China;School of Ecology and Environment,Inner Mongolia University,Hohhot 010021,China;Erguna Forest-Steppe Ecotone Research Station,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China;State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]大连民族大学环境与资源学院,大连116600 [2]内蒙古大学生态与环境学院,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,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

出　　处：《生态学报》2023年第17期7294-7306,共13页Acta Ecologica Sinica

基　　金：国家自然科学面上基金项目(31971464);辽宁省创新人才支持计划项目(辽教函[2020]389)。

摘　　要：草地覆盖全球陆地面积的40%左右,在全球碳循环中发挥着重要作用。近年来,人类活动,如化石燃料燃烧和畜牧业的发展显著增加了氮在全球环境中的沉积。草地管理方式(如刈割)在介导氮沉降对草地植物的影响方面具有重要作用。因此,筛选合适的模型对光响应过程进行拟合并计算相关参数对研究植物光合特性具有重要意义。依托6种氮添加(NH4NO3)梯度和两种草原管理方式(刈割和不刈割)交互处理的野外控制实验,利用Li-6400便携式光合作用系统测定上述实验平台的优势种羊草(Leymus chinensis)的光合作用-光响应过程。采用直角双曲线模型、非直角双曲线模型、指数模型和直角双曲线修正模型4种光响应模型对羊草光响应曲线进行拟合,从参数拟合效果和模型拟合优度筛选氮添加和刈割条件下羊草的最佳拟合模型并分析羊草的光合特性。结果表明:指数模型对表观量子效率(α)、光饱和点(LSP)和最大净光合速率(Pnmax)具有较好的参数拟合效果,非直角双曲线模型的模型拟合优度最好。在所有处理中,羊草均未表现出明显的光抑制现象,具有一定的光合潜力和适应环境变化的能力。适度氮添加和刈割处理能提高羊草净光合速率(Pn)、气孔导度(Gs)、Pnmax、α和LSP等,提升了羊草的光能利用率并拓宽了光强利用范围,但过度氮添加并不能进一步提高光合能力。综上,指数模型和非直角双曲线模型较适用于氮添加和刈割条件下羊草的光响应曲线拟合,施氮浓度为20 g N m^(-2)a^(-1)并刈割是最有利于提高羊草光合能力的草原管理措施。探讨了不同氮添加浓度和刈割处理对优势种羊草的交互影响,从光合作用角度分析羊草的适应机制,将对未来全球氮沉降增加情况下的草地管理方案提供科学依据。Grasslands cover approximately 40%of the global land surface area and play an essential role in the global carbon cycle.In recent years,human activities such as fossil fuel combustion and livestock development have significantly increased nitrogen deposition in the global environment.Grassland management,such as mowing,plays an important role in mediating the effects of nitrogen deposition on grassland plants.In addition,It is important to select suitable models to fit the process of light response and calculate the relevant parameters for studying the photosynthetic characteristics of plants.Based on the field control experiments with the interaction of six nitrogen(NH4NO3)gradients and two grassland management modes(mowing and non-mowing)in the Inner Mongolia meadow steppe,the photosynthesis-light response process of Leymus chinensis,the dominant species of the experimental platform,was determined.Four light response models,namely rectangular hyperbola model,non-rectangular hyperbolic model,exponential model and modified rectangular hyperbolic model,were used to fit the light response curves of L.chinensis.The best fitting model of L.chinensis was screened from the fitting effect of parameters and the fitting accuracy of the model,and the effects of nitrogen addition and mowing on light response characteristics of L.chinensis were analyzed.The results showed that the exponential model had the best fitting effect on the apparent quantum efficiency(α),light saturation point(LSP)and maximum net photosynthetic rate(Pnmax),while the non-rectangular hyperbolic model had the highest goodness of fit.In all treatments,L.chinensis did not show obvious photo inhibition,so it had a strongly photosynthetic potential and the ability to adapt to environmental changes.The net photosynthetic rate(Pn),stomatal conductance(Gs),Pnmax,α,and LSP of L.chinensis were increased under proper nitrogen addition and mowing treatment,the utilization rate of light energy of L.chinensis was increased and the utilization range of light inten

关 键 词：羊草 光响应模型 氮添加 刈割 光合特性 

分 类 号：S543.9[农业科学—作物学]