Acid Rain Treatment Research Articles

Long-Term Symptoms Due to Metal and Acid Precipitation Treatments in Scots Pine (Pinus sylvestris) Needles in the Subarctic

In naturally harsh environments, such as arctic-alpine regions, even low levels of anthropogenic pollution appear to have detrimental impacts on plants. We studied the symptoms induced by metal and acid rain treatments in the ultrastructure of Scots pine (Pinus sylvestris) needles in one of the northernmost pine stands in the world at the Kevo Subarctic Research Station, Finland. Adult Scots pines at their natural growing site were irrigated during 1991–1996 with (1) water, (2) acid (pH 3), (3) copper and nickel (below CuNi), (4) Cu and Ni combined with acid, or (5) left unirrigated. The two youngest needle age classes were sampled in September 1996 for microscopy and elemental analyses, and the three youngest needle age classes for an evaluation of visible injuries. The CuNi treatment increased significantly both Ni and Cu concentrations. The accumulation of Cu in C + 1 needles was enhanced by acid addition. CuNi addition did not increase visible injuries, but significantly more ultrastructural dark accumulations and swollen thylakoids were seen in CuNi-treated C + 1 needles. The results show that, even in a seemingly harsh environment, pines are able to resist acid and metal-induced stress for a few years. However, tree growth is likely to suffer in the long run because the injuries seen in older needles suggest that the total capacity of the photosynthetic machinery is likely to decrease.

The host plant‐mediated impact of simulated acid rain on the development and reproduction of Tetranychus cinnabarinus (Acari, Tetranychidae)

Abstract: The host plant‐mediated impact of simulated acid rain (pH 3.0, 3.5, 4.0, 5.6, and 6.8) on the behaviour, development, and reproduction of carmine spider mite, Tetranychus cinnabarinus (Boisduvals), were evaluated at 25°C in a series of laboratory trials. The results indicated that the adults of carmine spider mite prefer to aggregate on pH 4.0 acid rain‐treated eggplant leaves. The developmental times of nymph, larva and the pre‐oviposition period of the mite on kidney bean leaves were significantly affected by acid rain treatments. The developmental times for the immature stages ranged from 11.4 days on pH 4.0 acid rain‐treated leaves to 12.7 days on other acid rain‐treated leaves. The survival of immatures varied from 85.14% on pH 4.0 acid rain‐treated leaves to 78.83% on deionized water‐treated leaves (pH 6.8). The mites feeding on acid rain‐treated leaves (pH 3.0–5.6) had significantly greater reproductivity and longevity than those feeding on deionized water‐treated leaves. The average greatest reproductivity (74.6 eggs per female) and longest female longevity (8.9 days) were recorded on pH 4.0 acid rain‐treated leaves. Accordingly, the intrinsic rate of increase (rm) for the mite on pH 4.0 acid rain‐treated leaves was the highest. Jackknife estimates of rm varied from 0.201 on pH 4.0 acid rain‐treated leaves to 0.158 on pH 5.6 acid rain‐treated leaves. The results implied that the population growth of the mite were enhanced by application of acid rain (pH 3.0–5.6) on host plants.

Effects of Simulated Acid Precipitation on Photosynthesis, Chlorophyll Fluorescence, and Antioxidative Enzymes in Cucumis sativus L.

The effects of simulated acid rain on gas exchange, chlorophyll fluorescence, and anti-oxidative enzyme activity in cucumber seedlings (Cucumis sativus L. cv. Jingchun No. 4) were investigated. Acid rain significantly reduced net photosynthetic rate and mainly non-stomatal factors contributed to the decrease of photosynthesis during the experimental period. The reduced photosynthesis was associated with a decreased maximal photochemical efficiency (Fv/Fm) and the average quantum yield of the photosystem 2 (PS2) reaction centres (ΦPS2). Meanwhile, acid rain significantly increased the activities of guaiacol peroxidase (GPX) and superoxide dismutase (SOD), but decreased the activity of catalase (CAT) together with an increased content of malonyldialdehyde (MDA), Hence the changes in photosynthesis in acid rain treatment might be a secondary effect of acidity damage probably due to lipid peroxidation of lipids and proteins in thylakoid membrane rather than direct effect on PS2 reaction centre.

Oxidative stress and some antioxidant systems in acid rain-treated bean plants: Protective role of exogenous polyamines

The effect of simulated acid rain (AR) (pH 1.8) on H 2O 2 and malonyldialdehyde (MDA) levels and activities of peroxidase and catalase in bean plants were investigated. The influence of exogenous polyamines spermidine and spermine on these parameters was also studied. AR treatment induced lipid peroxidation and increased level of H 2O 2 in leaves. Pretreatment with spermidine and spermine prevented these changes. The protective effect of spermine was higher than that of spermidine. The impact of polyamines could be attributed to their acid neutralizing and antioxidant effects, as well as to their ability to stabilize membranes by associating with negatively charged phospholipids. It was also found that AR significantly increased peroxidase and decreased catalase activities at the first hours after treatment. Later, both enzyme activities were enhanced that could contribute to the scavenging and detoxification of active oxygen species.

Light and CO2 responses of photosynthesis and chlorophyll fluorescence characteristics in bean plants after simulated acid rain

The effects of simulated acid rain on some chlorophyll fluorescence characteristics and photosynthetic gas exchange at different light intensities and CO2 concentrations of bean plants were investigated. Measurements were carried out 3, 5 and 24 h after spraying. The results showed that a single acid rain (pH 1.8) treatment of bean plants reduced gas exchange, the maximal carboxylating efficiency and photochemical quenching. This treatment led also to increased CO2 compensation point and non‐photochemical quenching and changed the shape of CO2 and light curves of photosynthesis. Both stomatal and non‐stomatal factors contributed to the decreased photosynthetic rate, but their proportion changed with time of recovery of the photosynthetic ampparatus. Three hours after the treatment, the stomatal factors predominated in photosynthesis reduction, while during the next experimental period (5–24 h), mainly non‐stomatal factors determined the decreased photosynthetic rate. It is suggested that the effects observed in consequence of acid rain treatment could be due to an increased intracellular accumulation of H+ and harmful ions contained in the cocktail. This probably led to impaired membrane permeability, enhancement of stroma acidity, uncoupled electron transport and insufficient accumulation of ATP and NADPH, which affected carbon metabolism.

Sequential Effects of Acidic Precipitation and Drought on Water Relations of Pinus radiata Seedlings

In this work we investigated the sequential effects of simulated acid rain and drought on water relations of radiata pine ( Pinus radiata D. Don) seedlings. Whole seedlings were firstly subjected during 1 month to acid rain, pH 3.0, applied 5 times a week at 3 mm precipitation equivalent per day. Afterwards, drought treatment was applied by withholding water for 20 days and subsequent rewatering for 6 days to analyze the sequential effect of acid precipitation and drought. Water status parameters were determined before the initiation of acid rain treatment and within 3 weeks after the end of treatment. Acid rain treatment in well-watered plants did not affect either water potential or relative water content, whereas a marked effect on electrolyte leakage from the needles and on instantaneous transpiration was recorded. Drought treatment had great effects on leaf water potential (-2.5 MPa), RWC (50 % diminution), membrane permeability (340 % increase) and transpiration rate (25 % inhibition). Interactions involving acid precipitation and drought led to much greater impacts on all of the parameters analyzed. We conclude that although acid rain had slight, if any, direct effects on the water relations of well-watered radiata pine, it altered the drought tolerance of this tree species. Under conditions of soil-water deficit, plants exposed previously to acid rain are more sensitive to drought and desiccation.

A long-term study of the effects of simulated acid rain on birch leaf phenolics

Effects of prolonged simulated acid rain (sulphuric and/or nitric acids; two acidities, pH 4 and pH 3) on the phenolic biochemistry of mountain birch ( Betula pubescens ssp. czerepanovii) foliage was studied in the far north of Finnish Lapland. Even after 10 years of treatments, there was only one significant difference among the treatments: in mid-July, content of total phenolics was higher in birch leaves from acid rain treatments than in controls. On the other hand, differences among subares located close to each other were clearly larger than differences among the treatments. There were no significant differences among the treatments in contents of proanthocyanidins, total content of gallotannins or in contents of individual low molecular mass phenolics. In conclusion, phenolics of birch leaves do not seem to be sensitive to simulated acid rain.

Effects of exogenous polyamines applied separately and in combination with simulated acid rain on functional activity of photosynthetic apparatus

Ten-day-old bean seedlings ( Phaseolus vulgaris L.) were grown in a greenhouse and sprayed with spermidine or spermine. After 24 h they were treated with a cocktail of simulated acid rain (pH 5.6 and 1.8). Polyamines were applied separately or in combination with acid rain. Their protective effect on the functional activity of the photosynthetic apparatus in the acid rain-treated plants was investigated. It was found that acid rain with pH 1.8 applied separately decreased strongly the photosynthetic rate, the oxygen evolution, as well as the PS2 activity. Polyamines (spermidine and spermine) applied 24 h the before the acid rain treatment partially diminished the inhibitory effect of acid rain on the photosynthetic apparatus. The results showed also that the favourable effect of spermine was higher than that of spermidine. The protective action of polyamines could be explained by their polycationic nature, their ability to bind with photosynthetic membranes, resulting in conformational changes and stabilization, of the membrane and by their ability to act as free radical scavengers.

Responses of ground vegetation to prolonged simulated acid rain in sub‐arctic pine—birch forest

The effects of prolonged simulated acid rain on percentage cover of ground vegetation, and on growth and reproduction of two dominating dwarf shrubs (Emapetrum nigrum and Vaccinium vaitisidaea) were examined in a field experiment in the Finnish Subarctic, in an area with low ambient levels of sulphur and nitrogen deposition. Acid rain treatments included moderate (pH 3.8) and high (pH 2.9) concentrations of either H2 SO4 , or HNO3 , or a mixture of them, and were compared with irrigated (pH 6) and dry control plots. Long-term application of acid rain caused significant alteration in the cover and composition of ground vegetation. Effects of acid ram depended on the accompanying anion and on pH. Sub-plots under different canopy tree species differed in responses indicating that spatial heterogeneity is important in predicting the effect of acidifying pollution on this plant community. In the bottom layer, acid rain caused significant reduction in cover of the cyanobacterial lichens Nephroma arcticum and Peltigera spp. Decrease in cover of fruticose lichens, mainly composed of Cladina spp., more likely resulted from additional watering. In the field layer, acid rain containing moderate concentrations of NO- 3 caused an increase in cover of graminoid species. There were only slight alterations in growth and cover of the two dominant evergreen dwarf shrubs, Enigrum and V. vitis-idaea, indicating that these species are tolerant to acid rain of as low as pH 3. Even some positive responses of dwarf shrubs were observed, depending on canopy tree. Application of acid rain of pH 3 to plots under pine trees caused an increase in cover of I, vitis-idaea and, when the nitric acid only was applied, a short-term increase in the number of new shoots of E. nigrum. In contrast to vegetative growth, reproduction of the dwarf shrubs was more strongly affected by acid rain, but this also depended on local conditions and anion composition of acid rain. On 'pine' plots, rain of pH 3 reduced the number of berries and flower buds on terminal current shoot of E. nigrum, however, this was partially compensated by an increase in berry production at the ramet level. Simulated acid rain had mainly negative effects on berry production by V. vitis-idaea.

Growth Response of Subarctic Dwarf Shrubs, Empetrum nigrum and Vaccinium vitis-idaea, to Manipulated Environmental Conditions and Species Removal

We investigated the growth responses of two evergreen dwarf shrubs Empetrum nigrum and Vaccinium vitis-idaea to environmental manipulations (elevated temperature, increased precipitation and simulated acid rain) and to experimentally altered species composition in a three-year field experiment in the Finnish Subarctic. The responses of these species to experimental manipulations were highly complex, due to species-specific patterns of growth, great inter-annual variation and a high number of interactions between temperature, water and community composition. Both species showed increased shoot growth in the second and third season in response to elevated temperature. Elevated temperature also accelerated the vegetative bud break and shifted the peak shoot growth to an earlier time. The shoot growth of V. vitis-idaea was generally enhanced by additional irrigation, while the growth of E. nigrum tended to decrease in watered plots. Removal of heterospecific neighbours significantly modified growth responses to environmental manipulations. The positive effect of elevated temperature on E. nigrum was usually more profound on mixed species than on removal plots. The shoot growth of V. vitis-idaea was increased most when warming and watering were applied to plots of mixed species composition. The effect of the removal of companion species in turn depended greatly on environmental manipulations. Following the removal of V. vitis-idaea, E. nigrum generally increased branching, especially on open plots, and it increased the size of current shoots on open irrigated plots. However, when temperature was elevated, removal of V. vitis-idaea had negative effect on shoot growth and mass in E. nigrum. In V. vitis-idaea, current shoot size decreased after removal of E. nigrum on plots where either temperature or precipitation was increased. Only the most favourable conditions, on plots with both warming and watering, eliminated the negative effect of companion species removal on V. vitis-idaea. Acid rain treatment had no consistent effect on shoot growth of E. nigrum, while it greatly increased the production of adventitious shoots in V. vitis-idaea. The three years of experimental perturbations modified the shoot architecture markedly due to the effects of treatments on vegetative production per current shoot and the rate of lateral meristems activation. Changes in shoot architecture and phenology may be caused even by a short-term modification of climate and community composition, and may govern the success of these dwarf shrubs in a changing climate.

The effect of acid rain treatments on the susceptibility of Pinus sylvestris to Gremmeniella abietina

SummaryScots pine (Pinus sylvestris) seedlings were planted in a nursery bed 20 cm thick. The substrate had been removed from an illuvial horizon in the soil underlying a stand of Scots pine in Finland, which had suffered from severe infection by Gremmeniella abietina. The seedlings were irrigated for 3 years, applying three pH levels (2.5, 3.5, and 4.5) using sulphuric acid, nitric acid, and a 3:1 mixture of sulphuric and nitric acid. The pH of the pure water used in the control treatment was 6.1–6.4. The seedlings were inoculated with the conidiospores of G. abietina to find out their susceptibility to infection with the Scleroderris canker disease.Because to the adequacy of its buffering capacity, the soil was observed to become more acidic only in the treatments at pH 2.5. The concentrations of extractable Ca and Mg cations decreased while the concentration of Al and Fe increased with soil acidification during the 3‐year experiment. Acidification did not increase the susceptibility of Scots pine to infection by the Scleroderris canker. Seedling growth was at its maximum in the acidification treatments where most nitrogen was added.

Epicuticular wax of subarctic Scots pine needles: response to sulphur and heavy metal deposition

summaryThe response of epicuticular wax of Scots pine (Pinus sylvestris L.) needles to dry‐ and wet‐ deposited sulphur and heavy metals was investigated at six sites located 10–110 km from the Monchegorsk Cu‐Ni smelter on the Kola Peninsula, North‐West Russia, and in a long‐term irrigation experiment where pines were exposed over four growing seasons (1991–1994) to either acid rain treatment at pH 3.1 (H2SO4), metal treatment at pH 5.7 (Cu and Ni) or a combination of these at pH 3.1. Needle wettability exhibited a closer relationship with epistomatal wax tube distribution (WTD) than with chemical composition of epicuticular wax. Water droplet contact angles (DCA) decreased towards the smelter, and significant differences due to site were noted for 26‐month‐old and 38‐month‐old needles. Significant differences due to site were determined for secondary alcohols, dehydroabietic acid and hydroxy fatty acids, the proportions of which ranged from 22–5 to 48.9%, 6.2 to 224% and 0.6 to 2.6% respectively, depending on site and needle age class. The proportion of dehydroabietic acid increased towards the smelter, but no gradient was observed in the proportion of secondary alcohols or hydroxy fatty acids. No major effect of experimentally applied pollutants on the chemical composition or structure of the epicuticular wax was observed. The effect of treatment on DCA was significant in 1993 and 1994 due to a 6.5–13.2 degree greater wettability of the 37–49–month‐old acid‐treated needles relative to the irrigated or dry controls. Sulphuric acid at pH 3.1 did not increase needle wettability when combined with copper and nickel sulphate in similar concentrations. These data indicate that S deposition, especially H2SO4, plays a more important role in needle surface deterioration than Cu and Ni. Pollutant‐induced changes in epicuticular wax structure and needle wettability mimic natural wax ageing, but at an accelerated rate. Changes in wax chemical composition might also be caused by pollutant‐induced metabolic changes in elongating needles.

The Effect of Simulated Acid Rain on Surface Morphology and n-alkane Composition of Pseudevernia Furfuracea

The effects of simulated sulphuric acid rain were investigated, under controlled laboratory conditions, on the surface structure and n-alkane composition of the lichen Pseudevernia furfuracea. Thalli were collected from Larix decidua bark in a wood in a Piedmont alpine valley and treated with three concentrations of H2SO4. The response to simulated acid rain was a clear change in the quantitative alkane composition, with a decreasing trend observed for C28 and C30 with increasing sulphuric acid concentration. From a morphological point of view, a progressive reduction of the surface amorphous layer was observed as a consequence of the exposure of thalli to the acid rain treatments.

THE EFFECT OF SIMULATED ACID RAIN ON SURFACE MORPHOLOGY ANDn-ALKANE COMPOSITION OFPSEUDEVERNIA FURFURACEA

The effects of simulated sulphuric acid rain were investigated, under controlled laboratory conditions, on the surface structure andn-alkane composition of the lichenPseudevernia furfuracea. Thalli were collected fromLarix deciduabark in a wood in a Piedmont alpine valley and treated with three concentrations of H2SO4. The response to simulated acid rain was a clear change in the quantitative alkane composition, with a decreasing trend observed for C28and C30with increasing sulphuric acid concentration. From a morphological point of view, a progressive reduction of the surface amorphous layer was observed as a consequence of the exposure of thalli to the acid rain treatments.

Prolonged simulated acid rain treatment in the subarctic: Effect on the soil respiration rate and microbial biomass

Prolonged simulated acid rain treatment in the subarctic: Effect on the soil respiration rate and microbial biomass

Prolonged simulated acid rain treatment in the subarctic: Effect on the soil respiration rate and microbial biomass

Humus chemistry and respiration rate, ATP, ergosterol, and muramic acid concentration as measures of chemical properties, microbial activity, biomass, and indicators of fungal and bacterial biomass were studied in a long-term acid rain experiment in the far north of Finnish Lapland. The treatments used in this study were dry control, irrigated control (spring water, pH 6), and two levels of simulated acid rain (pH 4 and pH 3). Originally (1985–1988), simulated acid rain was prepared by adding both H2SO4 and HNO3 (1.9:1 by weight). In 1989 the treatments were modified as follows. In subarea 1 the treatments continued unchanged (H2SO4+HNO3 in rain to pH 4 and pH 3), but in subarea 2 only H2SO4 was applied. The plots were sampled in 1992. The acid application affected humus chemistry by lowering the pH, cation exchange capacity, and base saturation (due to a decrease in Ca and Mg) in the treatment with H2SO4+HNO3 to pH 4 (total proton load over 8 years 2.92 kmol ha-1), whereas the microbial variables were not affected at this proton load, and only the respiration rate decreased by 20% in the strongest simulated acid rain treatment (total proton load 14.9 kmol ha-1). The different ratios of H2SO4+HNO3 in subareas 1 and 2 did not affect the results.

The effect of “acid rain” and mineral fertilizers on the biometrical features of larix decidua mill. Seedlings

The purpose of the present experiment was to describe the influence of various mineral fertilizers on the development of Larix decidua Mill. seedlings subject to the influence of simulated acid rain of pH 2.5, 3.0, 3.5, 4.0, 4.5. The seedlings were fertilized every month (from April up to October), in order to counteract acid rain. The composition of the fertilizers was diversified in order to select an optimum variant. Fertilizer with NK applied to the needles (Florovit) and NPK applied to the soil (Fruktus 2) as well as dolomite lime applied to the soil. One row per set was left without fertilization as a control for each pH step of acid rain treatment. The analysis of biometric characteristics showed that a two-year period of investigations was too short to estimate effects on Larix decidua Mill. seedlings. It, however, indicated important trends. High correlations were found between particular growth parameters i.e. diameter of root neck, root mass, total mass of: seedlings, needles, main shoots, lateral shoots, ligneous parts, total overground parts. No strong correlations were observed between the above mentioned parameters and the total height of the seedlings. Among the different treatments the best development was achieved at pH 4.0, whereas the weakest development was observed at pH 2.5. The analysis showed a decrease in biometrical features along with an increase in acidity of acid rain solution. The first year of the experiment had the greatest influence upon the growth of Larix decidua Mill. seedlings. Significant improvement in growth, in relation to control plots, was achieved by using NK-fertilizers onto needles — the best results, and NPK onto soil. The best increment of the height of seedling was noticed at pH 3.5. In the second year of the experiment the effects of pH of acid rain and fertilization decreased — no significant effect on biometrical features was observed. Applaying NPK fertilizer onto soil showed a positive effect in relation to dolomite treatment. The best increment was noticed at pH 4.0.

Response of two cultivars of Triticum aestivum L. to simulated acid rain

The present experiment was aimed at assessing the impact of simulated acidic precipitation (SAR) on growth, biomass accumulation and yield of two cultivars of wheat ( Triticum aestivum L.), Malviya 206 and 234, varying in cuticular thickness and leaf area. Wheat cultivars were exposed to simulated rain acidified to pH 5.6 (control), 5.0, 4.5, 4.0 and 3.0 from 30 days of age, twice a week for five weeks. The plants received ambient precipitation of unknown acidity, as well as the acid rain treatments. Growth parameters such as shoot height, root length, and leaf area were reduced significantly in treated plants at different growth stages. Above and below-ground biomass also decreased significantly in the plants treated with acidic precipitation. Relative to control, the number of grains per plant and yield per m 2 declined significantly at all SAR treatments. The hypothesis that the variety with thinner cuticle and greater leaf area would be more susceptible to acidic precipitation was not supported by the present study.

Effect of acid deposition on soil acidification and metal mobilisation

Simulated acid rain treatments of pH 5.6, 4.0 and 2.5 in the laboratory produced marked acidification and Al and Zn mobilisation in columns of an homogenised incipient podsolic soil. Exposure of monoliths of the same soil and an acid brown earth to ambient levels of acid deposition in the U.K. for 3 a, resulted in soil acidification at higher rainfall and slightly contaminated sites, whilst the drier but more contaminated sites exhibited a more variable response. Changes in DTPA-extractable Zn did not conform to any obvious pattern, although at 5 of the 6 sites the acid brown earth monoliths underwent a decrease in Zn concentration.

Acid-rain-induced changes in cuticles and Ca distribution in Scots pine and Norway spruce seedlings

Seedlings of Scots pine (Pinussylvestris L.) and Norway spruce (Piceaabies (L.) Karst.) were subjected to acid rain irrigation at pH 7, pH 4, and pH 3 three times a week during the growing seasons of 1986–1989 in a field experiment. Scanning and transmission electron microscopy, energy dispersive spectrometry, contact angle measurements, and chloroform extraction of waxes were used to detect physicochemical changes in the needle cuticles. The first detectable symptoms of acid rain were observed after 5 weeks of acid rain treatment at pH 3 and pH 4, which resulted in few CaSO4 crystallites on visibly undamaged pine and spruce needle surfaces. After 7 weeks of acid rain treatment there were CaSO4 crystallites scattered over the whole needle surface area and erosion of the epicuticular waxes could be observed occasionally. CaSO4 crystal formation later decreased, especially on the needles of seedlings treated at pH 3. Ca concentrations in the needles and roots of the seedlings and in the soil in the boxes were higher in the pH 3 treatments than elsewhere. The more abundant deposition of Ca oxalate crystallites on the inner walls of the epidermal and hypodermal cells of the spruce needles than on their outer walls was probably also connected with Ca leaching, caused by acid rain. Acid rain also delayed wax synthesis, as 2-month-old pine needles exposed to pH 3 and pH 4 had about 50% less wax than the water controls in early August. The needle surfaces of the southern provenances of spruce and pine seedlings were slightly less wettable after pH 4 treatment than after the control water treatment, because they probably benefited from N and S compounds in the irrigation water. The needle surfaces were more wettable in the pH 3 and water control seedlings than in the other treatments.