Water stress rather than N addition mitigates impacts of elevated O3 on foliar chemical profiles in poplar saplings

Zhengzhen Li; Jian Yang; Bo Shang; Yansen Xu; John J Couture; Xiangyang Yuan; Kazuhiko Kobayashi; Zhaozhong Feng

doi:10.1016/j.scitotenv.2019.135935

Water stress rather than N addition mitigates impacts of elevated O₃ on foliar chemical profiles in poplar saplings

Sci Total Environ. 2020 Mar 10:707:135935. doi: 10.1016/j.scitotenv.2019.135935. Epub 2019 Dec 6.

Authors

Zhengzhen Li¹, Jian Yang², Bo Shang¹, Yansen Xu¹, John J Couture³, Xiangyang Yuan¹, Kazuhiko Kobayashi⁴, Zhaozhong Feng⁵

Affiliations

¹ 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 Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
³ Departments of Entomology and Forestry and Natural Resources, Purdue University, West Lafayette, IN 47906, USA.
⁴ Department of Global Agricultural Sciences, The University of Tokyo, Tokyo, Japan.
⁵ College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Ecology, 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: 31869612
DOI: 10.1016/j.scitotenv.2019.135935

Abstract

Tropospheric ozone (O₃) pollution can alter tree chemical profiles, and in turn, affect forest ecosystem function. However, the magnitude of these effects may be modified by variations in soil water and nutrient availability, which makes it difficult to predict the impacts of O₃ in reality. Here we assessed the effects of elevated O₃ alone, and in combination with soil water deficit and N addition, on the phytochemical composition of hybrid poplar (Populus deltoides cv. '55/56' × P. deltoides cv. 'Imperial'). Potted trees were grown in open-top chambers (OTCs) under either charcoal-filtered air or elevated O₃ (non-filtered air +40 ppb of O₃), and trees within each OTC were grown with four combinations of water (well-watered or water deficit) and nitrogen (with or without N addition) levels. We found that elevated O₃ alone stimulated the accumulation of foliar nitrogen, soluble sugar, and lignin while inhibiting the accumulation of starch, but had limited impacts on condensed tannins and salicinoids in poplar saplings. Graphical vector analysis revealed that these changes in concentrations of nitrogen, starch and lignin were due largely to altered metabolic processes, while increased soluble sugar concentration related mainly to decreased leaf biomass in most cases. The effects of O₃ on poplar foliar chemical profiles depended on soil water, but not soil N, availability. Specifically, O₃-mediated changes in carbohydrates and lignin were mitigated by decreased soil water content. Taken together, these results suggested that nitrogen acquisition, carbohydrates mobilization and lignification play a role in poplar tolerance to O₃. Moreover, the impacts of elevated O₃ on phytochemistry of poplar leaves can be context-dependent, with potential consequences for ecosystem processes under future global change scenarios. Our results highlight the needs to consider multi-factors environments to optimize the management of plantations under changing environments.

Keywords: Air pollution; Chemical defenses; Drought; Nutrient availability; Phytochemistry; Poplar plantation.

MeSH terms

Dehydration
Ecosystem
Ozone
Plant Leaves
Populus*

Substances

Ozone