Effects of elevated ozone on maize under varying soil nitrogen levels: Biomass, nitrogen and carbon, and their allocation to kernel

Jinlong Peng; Yansen Xu; Bo Shang; Evgenios Agathokleous; Zhaozhong Feng

doi:10.1016/j.scitotenv.2020.144332

Effects of elevated ozone on maize under varying soil nitrogen levels: Biomass, nitrogen and carbon, and their allocation to kernel

Sci Total Environ. 2021 Apr 15:765:144332. doi: 10.1016/j.scitotenv.2020.144332. Epub 2020 Dec 25.

Authors

Jinlong Peng¹, Yansen Xu², Bo Shang³, Evgenios Agathokleous³, Zhaozhong Feng⁴

Affiliations

¹ Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China; State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
² State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
³ Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China.
⁴ Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China. Electronic address: zhaozhong.feng@nuist.edu.cn.

PMID: 33385814
DOI: 10.1016/j.scitotenv.2020.144332

Abstract

Effects of ozone (O₃) on maize have been increasingly studied, but only few studies have focused on the combined impacts of O₃ and nitrogen (N) on this important crop with C₄ carbon (C) fixation. In this study, a maize cultivar with the largest acreage in China was exposed to two O₃ treatments (NF: ambient air O₃ concentration; NF60: NF plus 60 ppb O₃) and four N levels (farmers' N practice: 240 kg N ha^-1 yr^-1; 150%, 50% and 25% of farmers' N practice). Generally, O₃ and N significantly influenced biomass, N and C, but did not change their allocation to kernel. There were significant interactions between O₃ and N in stem biomass, C concentration and uptake, and leaf biomass and C uptake, with significant O₃ effects mainly occurring at N120 and N240. Based on the coefficient of determination (R²), root C:N ratio rather than the most commonly used leaf C:N ratio was the best trait to indicate maize productivity. Furthermore, O₃ significantly increased the regression slopes between root C:N ratio and kernel N uptake, kernel C uptake and plant N uptake, strengthened the correlation of C:N ratio and kernel C uptake, and weakened the correlation of C:N ratio and hundred-kernels weight. These suggest that O₃ pollution can change the relationship of C:N ratio and productivity in maize. The weak correlation between kernel harvest index (HI) and N harvest index (NHI) indicated that future breeding researches should consider how to improve the coupling between biomass and N-related nutrition allocations in crop edible parts. Our results not only are helpful to accurately estimate O₃ impacts on maize with consideration of N but also provide a new insight into the relationship between plant traits and its productivity under O₃ pollution.

Keywords: Air pollution; Carbon:Nitrogen ratio; Crop production; Plant traits; Sensitivity.

MeSH terms

Biomass
Carbon
China
Nitrogen
Ozone* / analysis
Plant Breeding
Plant Leaves / chemistry
Soil
Zea mays

Substances

Soil
Ozone
Carbon
Nitrogen