Effects of sulfuric, nitric, and mixed acid rain on Chinese fir sapling growth in Southern China

Xin Liu; Zhiyuan Fu; Bo Zhang; Lu Zhai; Miaojing Meng; Jie Lin; Jiayao Zhuang; G Geoff Wang; Jinchi Zhang

doi:10.1016/j.ecoenv.2018.04.071

Effects of sulfuric, nitric, and mixed acid rain on Chinese fir sapling growth in Southern China

Ecotoxicol Environ Saf. 2018 Sep 30:160:154-161. doi: 10.1016/j.ecoenv.2018.04.071. Epub 2018 May 26.

Authors

Xin Liu¹, Zhiyuan Fu¹, Bo Zhang², Lu Zhai³, Miaojing Meng¹, Jie Lin¹, Jiayao Zhuang¹, G Geoff Wang⁴, Jinchi Zhang⁵

Affiliations

¹ Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China.
² Department of Biology, University of Miami, Coral Gables, FL 33124, USA.
³ Southeast Environmental Research Center, Florida International University, Miami, FL 33199, USA.
⁴ Department of Forestry and Environmental Conservation, Clemson University, Clemson, South Carolina 29634, USA.
⁵ Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China. Electronic address: zhang8811@njfu.edu.cn.

PMID: 29803190
DOI: 10.1016/j.ecoenv.2018.04.071

Abstract

The influence of acid rain on plant growth includes direct effects on foliage as well as indirect soil-mediated effects that cause a reduction in root growth. In addition, the concentration of NO₃^- in acid rain increases along with the rapid growth of nitrogen deposition. In this study, we investigated the impact of simulated acid rain with different SO₄^2-/NO₃^- (S/N) ratios, which were 1:0, 5:1, 1:1, 1:5 and 0:1, on Chinese fir sapling growth from March 2015 to April 2016. Results showed that Chinese fir sapling height growth rate (HGR) and basal diameter growth rate (DGR) decreased as acid rain pH decreased, and also decreased as the percentage of NO₃^- increased in acid rain. Acid rain pH significantly decreased the Chlorophyll a (Chla) and Chlorophyll b (Chlb) content, and Chla and Chlb contents with acid rain S/N 1:5 were significantly lower than those with S/N 1:0 at pH 2.5. The chlorophyll fluorescence parameters, maximal efficiency of Photosystem II photochemistry (Fv/Fm) and non-photochemical quenching coefficient (NPQ), with most acid rain treatments were significantly lower than those with CK treatments. Root activities first increased and then decreased as acid rain pH decreased, when acid rain S/N ratios were 1:1, 1:5 and 0:1. Redundancy discriminant analysis (RDA) showed that the Chinese fir DGR and HGR had positive correlations with Chla, Chlb, Fv/Fm ratio, root activity, catalase and superoxide dismutase activities in roots under the stress of acid rain with different pH and S/N ratios. The structural equation modelling (SEM) results showed that acid rain NO₃^- concentration and pH had stronger direct effects on Chinese fir sapling HGR and DGR, and the direct effects of acid rain NO₃^- concentration and pH on HGR were lower than those on DGR. Our results suggest that the ratio of SO₄^2- to NO₃^- in acid rain is an important factor which could affect the sustainable development of monoculture Chinese fir plantations in southern China.

Keywords: Acid rain; Chinese fir; Chlorophyll; Growth rate; SO(4)(2−)/NO(3)(−) ratio.

MeSH terms

Acid Rain / toxicity*
China
Chlorophyll / metabolism
Chlorophyll A
Cunninghamia / drug effects*
Cunninghamia / growth & development
Cunninghamia / metabolism
Nitric Acid / toxicity*
Photosystem II Protein Complex / metabolism
Sulfuric Acids / toxicity*

Substances

Acid Rain
Photosystem II Protein Complex
Sulfuric Acids
Chlorophyll
Nitric Acid
chlorophyll b
sulfuric acid
Chlorophyll A