文献类型：期刊文献

英文题名：Physiological factors contribute to increased competitiveness of grass relative to sedge, forb and legume species under different N application levels

作者：Shen, Hao[1] Dong, Shikui[1,2,3] Ditommaso, Antonio[4] Westbrook, Anna S.[4] Li, Shuai[6] Zheng, Hanzhong[5] Zhi, Yangliu[2] Zuo, Hui[1] Wang, Qiyun[8] Liu, Junxiang[7]

第一作者：Shen, Hao

通信作者：Dong, SK[1]

机构：[1]Beijing Forestry Univ, Sch Grassland Sci, Beijing 100083, Peoples R China;[2]Beijing Normal Univ, Sch Environm, State Key Joint Lab Environm Simulat Pollut Contr, Beijing 100875, Peoples R China;[3]Cornell Univ, Dept Nat Resources, Ithaca, NY 14853 USA;[4]Cornell Univ, Sch Integrat Plant Sci, Soil & Crop Sci, Ithaca, NY 14853 USA;[5]Radboud Univ Nijmegen, Dept Environm Sci, NL-6526 AJ Nijmegen, Netherlands;[6]Shanxi Agr Univ, Coll Resource & Environm, Taigu 030801, Peoples R China;[7]Chinese Acad Forestry, State Key Lab Tree Genet & Breeding, Key Lab Tree Breeding & Cultivat, State Forestry Adm,Res Inst Forestry, Beijing 100091, Peoples R China;[8]Henan Univ, Sch Life Sci, State Key Lab Crop Stress Adaptat & Improvement, Kaifeng 475004, Peoples R China

年份：2024

卷号：906

外文期刊名：SCIENCE OF THE TOTAL ENVIRONMENT

收录：;EI(收录号：20234214912546);Scopus(收录号：2-s2.0-85174076599);WOS:【SCI-EXPANDED(收录号:WOS:001158925300001)】；

基金：This study was funded by the National Key R & D Program of China (2021YFE0112400) , the Second Tibetan Plateau Scientific Expedition and Research Program (2019QZKK0307) , and the National Science Foundation of China (U20A2007-01) .

语种：英文

外文关键词：Alpine meadow; Functional groups; Nitrogen deposition; Non-structural carbohydrates; Photosynthesis

摘要：In alpine grasslands, increased N deposition is increasing the dominance of grasses relative to other functional types according to our previous study Shen et al. (2022). However, the mechanisms that drive this compositional change are not fully understood. We measured the effects of 4-6 years' N addition to simulate N deposition at rates of 0 (CK), 8 (N1), 24 (N2), 40 (N3), 56 (N4), and 72 (N5) kg N ha-1 year-1 on dominant representatives of four functional types, Leymus secalinus (grass), Carex capillifolia (sedge), Potentilla multidi (non-leguminous forb), and Medicago ruthenica (legume), in the alpine grassland on the Qinghai -Tibetan Plateau (QTP). In -situ experiment showed that N addition increased aboveground biomass in L. secalinus but had negative or neutral effects on aboveground biomass in the other species. Consistent with this finding, N addition increased net photosynthesis, chlorophyll content, and rubisco activity in L. secalinus with less positive effects on the other species. Nitrogen addition increased leaf N content in L. secalinus and C. capillifolia and reduced leaf nonstructural carbohydrate content in all four species. In L. secalinus, the highest N addition rate (N5) reduced MDA content, a marker of oxidative stress, by enhancing antioxidant enzyme activity. Overall, our findings suggested that physiological factors can contribute to increased competitiveness of grass relative to sedge, forb and legume species under high N application levels. The rapid growth of this grass species reduces resource availability to non -grass species, increasing its dominance in the alpine meadow.