Ozone will remain a threat for plants independently of nitrogen load. (2nd September 2019)

• Record Type: Journal Article
• Authors: Feng, Zhaozhong; Shang, Bo; Li, Zhengzhen; Calatayud, Vicent; Agathokleous, Evgenios
• Editors: Stevens, Carly
• Is Part Of: Functional ecology. Volume 33:Number 10(2019)
• Page Start: 1854
• Page End: 1870
• Publication Date: 2019-09-02
• Subjects: air pollution -- biomass -- nitrogen deposition -- ozone -- photosynthesis -- stomatal conductance; Ecology -- Periodicals; 574.505
• DOI: 10.1111/1365-2435.13422
• Languages: English
• ISSNs: 0269-8463

Abstract

Abstract: Elevated concentrations of ground‐level ozone (O3 ) and atmospheric nitrogen (N) deposition occur concurrently. The negative effects of elevated O3 on plants have been widely studied and are well understood nowadays. However, how the effects of elevated O3 on plants may be driven by N deposition remains an unsolved puzzle. We conducted a meta‐analysis and showed that the negative effects of elevated O3 on photosynthesis, stomatal conductance, growth and biomass production of semi‐natural and natural vegetation may remain unchanged by N deposition in the coming future under realistic increases in O3 concentrations (+20 to 40 ppb) and N deposition (up to 60 kg ha −1 year −1 ). The negative effect of elevated O3 on chlorophyll content is offset by soil N addition; however, the negative effect on biomasses is not offset by soil N addition. Across functional groups and O3 levels, N addition exacerbated O3 effects on root when N increased from 0–10 kg N ha −1 year −1 to 11–30 kg N ha −1 year −1 . However, an analysis as per the plant functional group revealed that such a N‐dependent O3 effect was significant only in perennial non‐woody plants, and was non‐significant when only realistic increases in O3 concentrations were considered. Likewise, N addition appeared to exacerbate O3 ‐negative effects on photosynthesis of trees when N increased from 0–30 kg N ha −1 year −1 to >60 kg N ha −1 year −1 ; however, this effect was significant only when realistic increases in O3 concentrations were considered. The results suggest potential error in the current estimates of the overall O3 impacts on plants due to no consideration of soil N availability, and encourage further studies on the interaction of O3 and N availability that will permit more robust analyses in the future. Elevated O3 will likely remain a persistent agricultural and ecological issue independently of N deposition. A free Plain Language Summary can be found within the Supporting Information of this article. Abstract : A free Plain Language Summary can be found within the Supporting Information of this article.