Photosynthetic and growth responses of Schima superba seedlings to sulfuric and nitric acid depositions

Abstract

A continuing rise in acid deposition can cause forest degradation. In China, acid deposition has converted gradually from sulfuric acid deposition (SAD) to nitric acid deposition (NAD). However, the differing responses of photosynthesis and growth to depositions of sulfuric vs. nitric acid have not been well studied. In this study, 1-year-old seedlings of Schima superba, a dominant species in subtropical forests, were treated with two types of acid deposition SO4 (2-)/NO3 (-) ratios (8:1 and 0.7:1) with two applications (foliar spraying and soil drenching) at two pH levels (pH 3.5 and pH 2.5) over a period of 18 months. The results showed that the intensity, acid deposition type, and spraying method had significant effects on the physiological characteristics and growth performance of seedlings. Acid deposition at pH 2.5 via foliar application reduced photosynthesis and growth of S. superba, especially in the first year. Unlike SAD, NAD with high acidity potentially alleviated the negative effects of acidity on physiological properties and growth, probably due to a fertilization effect that improved foliar nitrogen and chlorophyll contents. Our results suggest that trees were damaged mainly by direct acid stress in the short term, whereas in the long term, soil acidification was also likely to be a major risk to forest ecosystems. Our data suggest that the shift in acid deposition type may complicate the ongoing challenge of anthropogenic acid deposition to ecosystem stability.

Nitrogen Deposition Enhances Photosynthesis in Moso Bamboo but Increases Susceptibility to Other Stress Factors

“…Inconsistent with the earlier findings that increased N application increases the chlorophyll content (Granath et al, 2009b ; Yao et al, 2016 ; Zhang et al, 2016 ), we found that chlorophyll content was not significantly affected by N deposition in Moso bamboo. A similar lack of response was also observed in R. squarrosus (Arróniz-Crespo et al, 2008 ).…”

Morphological, Physiological and Photophysiological Responses of Critically Endangered Acer catalpifolium to Acid Stress

“…The plant biomass accumulation also showed a similar trend consistent with previous results [ 27 , 28 ]. Direct acid spraying may damage the key components of the plant [ 3 ], resulting in the destruction of physiological functions (such as low P n and chlorophyll content) and then slow growth, which was consistent with previous findings [ 29 , 30 , 31 ].…”

“…High net photosynthetic rate in soil application treatments further explained better performance in growth and biomass accumulation [ 24 ]. However, the biomass improvement only appeared when treated with a low pH acid rain (the total biomasses of SL4.5 and NL4.5 were 316.30 ± 2.08 g and 309.10 ± 14.88 g), an observation which was reported in previous studies [ 3 , 24 ].…”

“…In this study, acid application methods simulated two influence pathways of acid rain on plant growth which included the direct effects on plant body and indirect effects from soil-mediated [ 23 ]. From the aspect of indirect effects, the biomass of A. catalpifolium under soil-applied acid treatments increased with the increasing acidity, which had similar change patterns with Schima superba and Elaeocarpus glabripetalus [ 3 , 24 ]. Furthermore, inputted N and S from acid rain may have compensated plant development.…”

“…Acid rain deposition (AR) has detrimental impacts on the functions of both terrestrial and aquatic ecosystems [ 1 , 2 ]. Sulfur dioxide and nitrogen oxide are major causative agents of acid rain resulting from anthropic emissions, such as the combustion of fossil fuels, agricultural production, and vehicle emissions [ 3 ]. Acid rain has been shown to significantly impede plant growth.…”