Short-term acid damage to photosynthesis in corn and sugar maple leaves assessed by photoacoustic spectroscopy

1990 ◽  
Vol 68 (10) ◽  
pp. 2292-2300 ◽  
Author(s):  
C. N. N'soukpoé-Kossi ◽  
R. Bélanger ◽  
S. Keilani ◽  
H. Proteau ◽  
P. Boivin ◽  
...  
Keyword(s):  
Growth Rate ◽  
Acid Rain ◽  
Oxygen Evolution ◽  
Photoacoustic Spectroscopy ◽  
Sugar Maple ◽  
Photosynthetic Activity ◽  
Simulated Acid Rain ◽  
Acid Mixture ◽  
Photosynthetic Oxygen Evolution ◽  
Ph Values

Photoacoustic spectroscopy was used to monitor acid damage to photosynthesis by measuring photosynthetic O2 evolution in leaves from com and sugar maple plantlets. For 2 months the seedlings were treated with simulated acid rain either by spraying the leaves or by watering the soil at different pH levels. The results indicated a decline of photosynthetic oxygen evolution as the pH of the foliar application of simulated acid rain decreased. The reduced photosynthetic activity was sometimes followed by depigmentation (below pH 3.5). For plantlets treated by watering the soil with an acid mixture, the results showed an increase in the growth rate at higher acidity levels without effect on the photosynthetic activity. All corn seedlings from seeds that germinated in media of different pH levels showed the same photosynthetic activity regardless of the pH, as measured by photoacoustic spectroscopy, but the growth rate was higher at lower pH values than at higher pH values. These results clearly indicate the importance of acid damage to photosynthesis at the foliar level, and the ability of photoacoustic spectroscopy to assess forest decline in its early stages. Key words: photoacoustic spectroscopy, photosynthesis, corn, maple, acid rain, oxygen evolution.

scholarly journals Mechanical Behavior and Constitutive Model for Loess Samples under Simulated Acid Rain Conditions

2021 ◽  
Author(s):  
xia ye ◽  
Enlong Liu ◽  
Baofeng Di ◽  
yayang yu
Keyword(s):  
Mechanical Properties ◽  
Acid Rain ◽  
Mechanical Model ◽  
Ph Value ◽  
Simulated Acid Rain ◽  
Test Results ◽  
Hardening Model ◽  
Ph Values ◽  
Scanning Electron ◽  
Peak Value

Abstract In this paper, the sulfuric acid solution is diluted to pH 5.0, 4.0 and 3.0 to simulate the acid rain condition, and the triaxial compressional tests and scanning electron microscope are carried out to study the mechanical properties and evolution of the microstructure of the saturated loess samples. The results demonstrate that acid rain increases the porosity of loess samples, and the pore distribution is not uniform, so that the mechanical properties of loess samples change. With the decrease of pH value, the peak value of the deviatoric stress and the volumetric contraction of loess samples decreases, which causes the strength of soil to decrease. Furthermore, the framework of the chemical-mechanical model for loess under the action of acid rain is established, in which the loess is considered as porous medium material, and the variable of acid rain at different pH values through the degree of chemical reaction is taken into account in the double-hardening model, and the model is also verified by the triaxial test results finally.

scholarly journals Experimental Study of the Quantitative Impact of Flow Turbulence on Algal Growth

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 659
Author(s):  
Haiping Zhang ◽  
Yafei Cui ◽  
Yuehong Zhang ◽  
Hanling Xu ◽  
Feipeng Li
Keyword(s):  
Growth Rate ◽  
Oxygen Evolution ◽  
Microcystis Aeruginosa ◽  
Algal Growth ◽  
Turbulent Intensity ◽  
Photosynthetic Oxygen Evolution ◽  
Photosynthetic Oxygen ◽  
Flow Turbulence ◽  
Study Laboratory ◽  
Algal Growth Rate

Flow turbulence has been widely accepted as one of the essential factors affecting phytoplankton growth. In this study, laboratory cultures of Microcystis aeruginosa in beakers were carried out under different turbulent conditions to identify the quantitative relationship between the algal growth rate and the turbulent intensity. The turbulent intensity (represented by energy dissipation rate, ε) was simulated with the software FLUENT. Daily measurement of the two parameters (algal biomass and chlorophyll-a concentration) was carried out during the experimental period to represent the algal growth rate. Meanwhile, the rates of photosynthetic oxygen evolution and chlorophyll fluorescence intensity were calculated to investigate the photosynthetic efficiency. The results indicated that the growth rate of Microcystis aeruginosa became higher in the turbulent environment than in the still water environment under the designed experimental conditions. The peak growth rate of Microcystis aeruginosa occurred when ε was 6.44 × 10−2 m2/s3, over which the rate declined, probably due to unfavorable impacts of strong turbulence. In comparison, the maximum rate of photosynthetic oxygen evolution occurred when ε was 0.19 m2/s3. Based on the findings of this study, an exponential function was proposed in order to incorporate the effect of flow turbulence into the existing algal growth models, which usually just consider the impacts of nutrient availability, illumination, and temperature.

Effects of simulated acid rain on growth rate in a spruce-living spider

1989 ◽  
Vol 56 (4) ◽  
pp. 311-317 ◽  
Author(s):  
Bengt Gunnarsson ◽  
Jörgen Johnsson
Keyword(s):  
Growth Rate ◽  
Acid Rain ◽  
Simulated Acid Rain

scholarly journals Growth and Leaf Chlorophyll Content of Eucalyptus grandis W. Hill ex Maiden are Adversely Affected by Simulated Acid Rain

2020 ◽  
pp. 8-15
Author(s):  
Langmi Fabrice Buma ◽  
Titus Fondo Ambebe ◽  
Zephania Nji Fogwe
Keyword(s):  
Acid Rain ◽  
Chlorophyll Content ◽  
Tap Water ◽  
Harmful Effect ◽  
Eucalyptus Grandis ◽  
Simulated Acid Rain ◽  
Total Biomass ◽  
Leaf Chlorophyll Content ◽  
Ph Values ◽  
Leaf Chlorophyll

The study assessed the effects of different pH values of simulated acid rain on growth and leaf chlorophyll content of Eucalyptus grandis. The treatments comprised of two simulated acid rain solutions of pH 4.0 and 3.5, and unacidified water at pH 6.5. Place and Duration of Study was the National Forestry Development Agency, Humid Savannah Zone, Bamenda I Sub-Division, North West Region, Cameroon, between June and September 2019, respectively. The experiment was conducted under field conditions. Thirty 3-month-old seedlings were exposed to each pH level at 7-day intervals using a spray bottle. While two sets of thirty seedlings were administered sulphuric acid calibrated tap water with pH values of 4.0 and 3.5, the third set that constituted the control was sprayed with normal tap water. Data were collected on morphology, biomass, and leaf chlorophyll content at the end of the study and subjected to analysis of variance and Scheffé’s test. Results: The pH 3.5 treatment resulted in significantly lower responses of height (12.95 cm), number of leaves (15.28), leaf area (23.96 cm2) and total biomass (0.61 g) than the other two pH levels that did not differ for any of the traits. Average values between pH 4.0 and control were 20.39 cm, 22.00, 45.66 cm2 and 1.77 g. Stem diameter and root collar diameter declined from 2.87 mm and 4.14 mm at the control to 2.54 mm and 3.78 mm at pH 3.5, respectively. Leaves at pH 3.5 showed signs of necrosis, drying and curling. Leaf chlorophyll content was significantly greater in the control (45.30 SPAD units) than in the pH 4.0 (40.01 SPAD units) and pH 3.5 (39.82 SPAD units) treatments that displayed similar responses. Conclusion: The study reveals that simulated acid rain at pH 3.5 can have a harmful effect on chlorophyll content and growth of Eucalyptus grandis.

Impact of simulated acid rain on microbial respiration, biomass, and metabolic quotient in a mature sugar maple (Acersaccharum) forest floor

1996 ◽  
Vol 26 (8) ◽  
pp. 1446-1453 ◽  
Author(s):  
Chandini M. Thirukkumaran ◽  
Ian K. Morrison
Keyword(s):  
Adverse Effects ◽  
Acid Rain ◽  
Forest Floor ◽  
Sugar Maple ◽  
Microbial Respiration ◽  
Microbial Biomass Carbon ◽  
Combined Treatment ◽  
Simulated Acid Rain ◽  
Experimental Conditions ◽  
Substrate Induced Respiration

Effects of simulated acid rain on forest floor microbiological processes were investigated in an old-growth sugar maple (Acersaccharum Marsh.) woods at Turkey Lakes Watershed, northern Ontario, Canada. Sulphate and NO3− in ambient precipitation received on four replicate plots were augmented with additions of dilute (0.02 N) H2SO4 and HNO3, applied alone and in combination periodically during the growing seasons of 1993 and 1994. The equivalent load of SO42− applied in the present experiment was ca. 6 times that in ambient precipitation in the H2SO4-only treatment and half that in the combined treatment over the study period. In situ soil respiration measured during the summer and fall of 1994 showed no adverse effects of acid treatment. In the laboratory, soil microbial respiration, biomass (as determined by substrate-induced respiration), and microbial biomass carbon: organic carbon (Cmic/Corg ratios were significantly depressed in the L or FH layers of the forest floor when H2SO4 was applied alone or in combination with HNO3. No effects of HNO3 were detected when applied alone. Microbial respiration, substrate-induced respiration, and Cmic/Corg ratios were significantly correlated with forest floor pH. Microbial metabolic quotients (respiration:biomass ratios) were not adversely affected by any of the treatments. The observed deleterious effects of H2SO4 application under experimental conditions suggest the possibility of adverse effects in the field over the long-term.

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