内蒙古草原优势物种光合速率对极端干旱的响应  

The responses of photosynthetic rate of dominant species to extreme drought in Inner Mongolia grasslands

作　　者：Yalong Shi Yuanbo Cao Honghui Wu Chong Xu Qiang Yu Xiaoan Zuo Xingguo Han Melinda D.Smith Alan K.Knapp Chengjie Wang Guodong Han 

机构地区：[1]State Key Laboratory of Effcient Utilization of Arid and Semi-arid Arable Land in Northern China,Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,China [2]Key Laboratory of Arable Land Quality Monitoring and Evaluation,Ministry of Agriculture and Rural Affairs,Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,China [3]China Rida Investment and Development Group Corp Ltd,Beijing 100040,China [4]School of Grassland Science,Beijing Forestry University,Beijing 100083,China [5]Urat Desert-grassland Research Station,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China [6]State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China [7]Department of Biology and Graduate Degree Program in Ecology,Colorado State University,Fort Collins,CO 80523,USA [8]College of Grassland,Resource and Environmental,Inner Mongolia Agricultural University,Hohhot 010011,China

出　　处：《Journal of Plant Ecology》2024年第3期5-15,共11页植物生态学报（英文版）

基　　金：National Key Research and Development Program of China(2019YFE0117000);National Natural Science Foundation of China(32171651,31971533).

摘　　要：评估极端干旱对优势植物物种光合速率(Pn)的影响对于我们理解极端干旱影响生态系统功能的机制至关重要。极端干旱可能由降雨量减少或降雨频率减少造成。这两种不同模式的极端干旱可能造成不同的影响。此外,不同草原类型可能对这两种极端干旱模式表现出不同的敏感性。然而,目前尚不清楚这两种极端干旱模式对草原优势植物物种Pn的影响有何差异,以及在不同草原类型这两种不同模式的极端干旱的效应是否改变。为此,我们于2014年在内蒙古草原两个不同类型的草原(荒漠草原vs.典型草原)站点各进行了一项多年的极端干旱(CHR:将生长季期间每次降雨事件的降雨量减少66%vs.INT:完全排除生长季内一段较短时间的降水)模拟实验。于2017年的7月和8月,我们在这两个草原站点各测量了两种优势物种的Pn。结果发现,CHR和INT均显著降低了优势物种的Pn。无论草原类型如何,INT对Pn造成的负面影响都更大。在荒漠草原,极端干旱对Pn的负面影响普遍大于典型草原,尤其是对于CHR处理下的羊草(Leymus chinensis)。这些结果表明,与降雨量减少相比,降雨频率减少所引起的极端干旱对Pn的负面影响更大。草地类型可能会改变极端干旱模式效应的程度,但不会改变其方向。这些发现强调了应对未来极端干旱的草原生态系统管理应考虑极端干旱模式和草地类型的影响。Estimating the effects of extreme drought on the photosynthetic rates(Pn)of dominant plant species is crucial for understanding the mechanisms driving the impacts of extreme drought on ecosystem functioning.Extreme drought may result from either reduced rainfall amount or decreased rainfall frequency,and the impacts of different patterns of extreme drought may vary greatly.In addition,different grasslands likely appear various sensitivity to different extreme drought patterns.However,there have been no reports on the effects of different extreme drought patterns on dominant species Pn in different grassland types.Here,we conducted multi-year extreme drought simulation experiments(reducing each rainfall event by 66%during the growing season,CHR vs.completely excluding rainfall during a shorter portion of the growing season,INT)in two different grasslands(desert grassland vs.typical grassland)from 2014.The Pn of two dominant species in each grassland was measured in July and August 2017.Both CHR and INT signifcantly decreased dominant species Pn,with INT causing more negative impacts on Pn regardless of grassland types.The response ratios of Pn in desert grassland were generally higher than that of typical grassland,especially for Leymus chinensis in CHR.These results demonstrated that decreased rainfall frequency had a more negative effect on Pn compared with reduced rainfall amount,with grassland types changing the magnitude,but not the direction,of the effects of extreme drought patterns.These fndings highlight the importance of considering extreme drought patterns and grassland types in ecosystem management in the face of future extreme droughts.

关 键 词：极端气候 荒漠草原 典型草原 极端干旱模式 季节性干旱 

分 类 号：S812[农业科学—草业科学]