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1.
Three-year old cuttings of Japanese cedar (Cryptomeria japonica), Japanese cypress (Chamaecyparis obtusa) and Sawara cypress (Chamaecyparis pisifera) were grown in pots with andosol and were exposed to simulated acid rain (SAR) at pH 2.0, 3.0, and 4.0 for 23 months. Total precipitation was 2460, 3960, or 5450 mm and SAR contained sulfuric, nitric and chloric acid at equivalent ratio of 5∶2∶3. Deionized water of pH 5.6 was a control. Exposure to SAR at pH 2.0 induced visible foliar injuries, but not any visible symptoms at pH 3.0 or higher. Total dry weights of 3 conifer cuttings grown with fertilizer were about two fold of those in plants grown without fertilizer and they reduced significantly by the exposure to SAR at pH 2.0. However, Cryptomeria japonica without fertilizer increased dry weights even though plants developed reddish-brown necrosis in large parts of tops. These 3 coniferous cuttings did not show any significant growth reduction at pH 3.0 and 4.0. Soil pH after receiving 5450 mm of SAR at pH 2.0 was 4.0 and molar ratio of (K+Ca+Mg)/Al in water and 1M ammonium acetate soluble fraction of the soil was about 0.3 and 0.4. respectively. However, dry weight of root in plants grown without fertilizer did not decrease. This suggested that growth reduction in plants fertilized and exposed to pH 2.0 was due to a reduction in photosynthetic organs associated with visible injuries, but not direct linkage with root growth inhibition due to soil acidification stress.  相似文献   

2.
Soybean seedlings (Glycine max) were exposed to simulated acid rain containing sulfate ion only or a mixture of sulfate, nitrate and chloride anions, using a continuous rain generating system in a side opened glasshouse. Plants were subjected to acid rain treatment twice a week, for a 1 or 3 hr period at a rate of 2.2 or 5.0 mm hr?1, respectively. Dry seed yield in plants treated with simulated acid rain at pH 2.0, in the three of 4 experiments conducted over a 3 yr period, was significantly less than that at pH 3.0 or higher. Simulated acid rain treatment at pH 3.0 or higher did not significantly affect yield compared to pH 5.6; however, plants exposed to simulated acid rain at pH 4.0 tended to yield more than those treated with pH 5.6 rain. Based on the current 3 years of research in which results from 4 experiments were combined, rain acidity at current levels in Japan would not directly affect seed production of selected cultivars of soybean.  相似文献   

3.
Over the last several decades rain in the Northeastern United States has become more acidic presumably as a result of anthropogenic inputs of SOx and NOx to the atmosphere and their conversion to H2SO4 and HNO3. Present experimental results suggest that acidic precipitation would initially affect organisms on leaf surfaces and epidermal cells of leaves of higher plants. More internal cell layers would be affected with increasing duration or frequency of exposure. Differences in responses of plant foliage among plant species to acidic precipitation appear to be due to the degree of leaf wetting and differences in responses of leaf cells to low pH rain. Moreover, within the same plant, particular structures or cell types may be more sensitive than others. If the United States is to utilize coal reserves for electric power generation that might increase rainfall acidity in the future, an assessment of the impact that acidic rain might have on terrestrial vegetation is necessary. In one experiment, field-grown soybeans were exposed to short duration rainfalls of either pH 4.0, 3.1, 2.7, or 2.3 to provide inputs of 50, 397, 998, or 2506 μeq of H+, respectively, above ambient levels throughout the growing season. Control plots received only ambient rainfalls. These additional H+ decreased seed yield, 2.6, 6.5, 11.4, and 9.5%, respectively. A treatment response function determined between H+ treatments and seed yield wasy=21.06?1.01 logx had a correlation coefficient of ?0.90. Researchers must design additional experiments with adequate experimental controls to assess the impact that acidic rain, at the present pH levels of 3.0 to 4.0 or at anticipated worst-case levels, that could occur if the acidity of rain should increase. Only a holistic view of the impacts that acid precipitation may have on vegetation will enable optimal energy and environmental policy decisions to be made.  相似文献   

4.
Seeds of red pine (Pinus densiflora Sieb. and Zucc.) were sown in red-yellow soil artificially adjusted to pH (H2O) 4.10, 4.60 or 5.90 by adding H2SO4 solution to the soil (pH 5.90), and the three-month seedlings were exposed to simulated acid rain at pH 2.0, 3.0 or 5.6 for 10 minutes once, 3 times a week, for 12 months from 4 August 1994 to 3 August 1995 alone or in combination. Significant interactive effects between acid rain and soil acidification on growth and whole-plant net photosynthetic rate, and cold death ratio of new apical shoots following a cold snap were observed in a quadratic response pattern. The simulated acid rain increased budburst, new needle spread and elongation, and new apical shoot death percentage following a cold snap, but did not induce visible injury. In the highest soil acidity treatment at a soil pH 4.1, whole-plant net photosynthetic rate and seedling height exhibited a quadratic responses with increasing rain acidities. On the other hand, soil acidification caused leaf yellowing. The death percentage of new apical shoot of seedlings exposed to rain pH 2.0 following a cold snap was linearly enlarged with increasing soil acidities. With increasing soil acidity, height and whole-plant net photosynthesis of the seedlings exposed to rain pH 3.0 exhibited a linear increase response, while height of seedlings exposed to control rain exhibited a quadratic response. It is suggested that the results provide experimental evidency for phenological disturbances and an enhancement of frost risk by direct acid rain and indirect longterm soil acidification which may be significant in forest decline.  相似文献   

5.
The lichensPseudoparmelia caperata (L.) Hale,Usnea ofsubfusca Stirt., andUmbilicaria mammulata (Ach.) Tuck. were exposed to simulated acidic rain with pH levels of 2.3, 3.0, 3.3, 4.3, or 5.6 and other. ions in concentrations normally found in rain in the eastern United States. The pH levels of the most acidic treatments (3.3, 3.0, 2.3) were similar to those found in fog, cloud water, and occasional rainfall events. The pH 4.3 and 5.6 treatments compared to average ambient conditions in the eastern and western United States, respectively, and caused no significant effects on photosynthesis. However, after the first week of treatment, significant effects of rain pH at the most acidic treatments on gross photysnthesis were detected inP. caperata andU. mammulata, but not inU. cfsubfusca. Visible effects of injury were also observed and included bleaching, necrotic spots, and necrotic margins, which resembled damage seen in field populations ofU. mammulata, the most sensitive species.  相似文献   

6.
Mycorrhizal infection but not growth of white pine seedlings was reduced by application of simulated rain at pH 3.5 at 3 times ambient rates to plants grown in steamed Mardin soil inoculated with Pisolithus tinctorius. In unsteamed Mardin soil, the simulated acid rain at 3 times ambient rates had no effect on mycorrhizal infection or growth of pine seedlings if the rain was applied to the plants and soil or to only the soil before planting, except that nitrate-containing acid rain increased growth, infection and N content. In limed Mardin soil, the simulated acid rain reduced mycorrhizal infection if applied to the plants and soil as the seedlings were growing but not if applied to the soil before planting. Application of pH 3.5 rain at ambient rates had no detectable influence on mycorrhizal infection in 6 of 9 soils tested, but it stimulated infestion in 3 soils if the simulated rain contained only sulfate and in 1 soil if it had both sulfate and nitrate.  相似文献   

7.
One-year-old loblolly pine seedlings were exposed to 03(≤0.025 or 0.10 μ L L?1, 4 hr d?1, 3 d wk?1) in combination with simulated rain (pH 5.6 or 3.0, 1 hr d?1, 2 d wk?1, 0.75 cm hr?1) for 10 wk. After the 10-wk treatment, the seedlings were submitted to two drought cycles, and water potential, net photosynthesis (Pn), and transpiration (Tr) were measured. Whole-plant fresh weight increment and relative growth rate were significantly increased in seedlings exposed to simulated rain at pH 3.0 compared to pH 5.6. An interaction between 03 and simulated rain occurred in height growth. Shoot height elongation was significantly less in seedlings exposed to 0.10 μL L?1 03 + pH 5.6 than in any other pollutant combination after the 10-wk treatment period. There were no significant effects of 03 on Pn and Tr prior to the drought cycles; however, after the first drought cycle, Pn was significantly higher in seedlings pre-exposed to 0.10 μL L?1 03 compared to the low 03 concentration. The 10-wk treatment with simulated rain at pH 3.0 significantly increased Pn and Tr. The relationship between gas exchange rates and needle water potential during the moisture stress period was affected by preexposure to pollutants. In general, Pn and Tr were more sensitive to decreasing needle water potential in seedlings exposed to pH 3.0 during the first drought cycle and to 0.10 μL L?1 03 during second drought cycle.  相似文献   

8.
The impacts of simulated acid rain on leachability of major plant nutrients, toxic element [aluminum (Al)], and acidity development in highly weathered tropical soils of Thailand were studied. Leaching experiments were conducted on soil columns with acidic solutions of pH 5.0, 4.0, 3.0, 2.0, and with water of pH 7.0 as a control treatment. Leaching losses of base cations from all soils increased with the decrease in pH associated with simulated acid rain (SAR) additions, and were found to be quite high under SAR with pH 2.0. The leaching removal of these cations was lesser at pH 3.0, 4.0, and 5.0 but greater than that in pH 7.0. The leaching of base cation from the soils depended not only on acid rain pH but also on soil properties, especially cation exchange capacity, soil texture, and initial base content. The significant losses of major plant nutrients [such as potassium (K+), calcium (Ca2+), and magnesium (Mg2+)] from the plant root zone over extended periods could cause nutrient imbalance and lower soil productivity.  相似文献   

9.
采用叶面喷洒模拟酸雨方法,研究了30种草本观赏植物对酸雨急性伤害的反应。试验结果表明,随酸雨胁迫强度增强,多数草本观赏植物叶片伤斑面积加大。当酸雨pH达2.0时,所有植物叶片均出现伤斑,其中近半数种类叶片伤斑面积>20%。30种草本观赏植物中敏感植物3种,占10.0%;抗性植物17种,占56.67%;中等抗性植物10种,占33.33%。在设定的酸雨胁迫强度(pH 2.0~3.5)下,多数植物的伤害阈值可被确定,惟有羽衣甘蓝、三色堇和葱兰在pH 2.0酸雨胁迫下仍无法确定其伤害阈值,表明此3种草本观赏植物对酸雨有极强抗性。试验表明30种受试草本观赏植物抗酸雨能力强弱与叶片细胞pH变化有关,即叶片细胞pH缓冲能力影响了酸雨对叶片的表观伤害效应。  相似文献   

10.
Simulated H2SO4 rain (pH 3.0, 3.5, 4.0) or control rain (pH 5.6) was applied for 3.5 yr to large lysimeter boxes containing a sulfate-adsorbing forest soil and either red alder (Alnus rubra Bong) or sugar maple (Acer saccharum Marsh.) seedlings. After removal of the plants and the litter layer, soil samples were obtained at 15-cm intervals to a total depth of 90 cm. Elevated SO4 concentrations caused by the simulated H2SO4 rain were most pronounced for the top 15 cm, but extended down to 45 cm (maple) or 75 cm (alder). There were no effects on SO4 concentrations at a depth of 75 to 90 em. This confirmed the existence of a sulfate front between 20 cm and 100 cm, as postulated earlier on the basis of extracted soil solutions. Decreases in Mg and Ca concentrations, base saturation, and soil pH were limited to the uppermost 15 cm and, in most cases, to the pH 3.0 treatment. Concentrations of Mg and Ca for the pH 3.0 treatments were greater than control at a depth of 15 to 30 cm, indicating transport of these cations from the soil surface. Concentrations of Na and K, and cation exchange capacity, were not affected by simulated H2SO4 rain. Elevated concentrations of NO3 and extractable Zn throughout the alder systems indicated (1) either increased rates of symbiotic N-fixation or decreased rates of N immobilization; and (2) mobilization of Zn by all acid rain treatments.  相似文献   

11.
Abstract

A comparison was made between three acidified, simulated rain treatments which have been used to assess the impact of acid rain on soil chemical and microbial processes. There were significant differences in effects on chemical and microbial characteristics of soil exposed to the three treatments due to differences in the rate of H+ ion application, even though the total quantity of protons supplied was the same in each case. An input of 30 cm of simulated rain of pH 3.0 over 6 months increased microbial activity and caused only slight changes in soil pH and soil nitrogen status. Treatments in which the rate of H+ input was accelerated by increasing solution volume, or acidity, inhibited microbial activity and caused soil chemical changes in excess of those produced by the more gradual yet equivalent H+ loading. We conclude that the effects of short‐term, accelerated acid treatments cannot be used to realistically forecast long‐term impacts of acid rain. The results of such experiments may be useful in identifying processes or parameters for studies of longer duration.  相似文献   

12.
The present study reports the results of a field-basedexperiment conducted to assess the effect of simulated acid rain(SAR) of different pH i.e. 5.6 (control), 5.0, 4.5, 4.0 and 3.0on two cultivars of wheat (Triticum aestivum, Malviya 213(M213) and Sonalika). Shoot and root lengths significantlydeclined at pH 3.0 in both varieties. Leaf area declined at pH4.0 and 3.0 in M213 at both ages and at 75 days in Sonalika.Total biomass of 75 days plants declined significantly at pH range4.5–3.0 in M213 and at pH 4.0 and 3.0 in Sonalika. Netassimilation rate (NAR) declined significantly at pH 3.0 inboth varieties. Compared to control, yield of M213 showedsignificant reductions at pH 4.0 and 3.0, whereas Sonalikaresponded negatively at pH 3.0. The study showed that acid rainhas a significant negative effect on wheat plant performance.  相似文献   

13.
Simulated acid rains of pH 5.6, 4.0, 3.5, 3.0, 2.5, or 2.0 were applied to leaves of broadleaf tobacco twice per week for 1, 2, 3, 4, or 5 weeks. Only those plants receiving rain of pH 2.0 were injured and, among those, the plants receiving fewer applications had less severe injury. Foliar symptoms resembled weather fleck (O3 injury) at first, but become distinguishable from them with time.  相似文献   

14.
模拟酸雨对不同园林植物叶片生理生态特性的影响   总被引:2,自引:0,他引:2  
采用盆栽方法,以自来水(pH值6.5)作为对照,研究了pH值为1.7,3.0,4.3,5.6模拟酸雨条件下新梢增长量、叶片损伤程度和叶片生理生态特性,并分析了园林植物对酸雨污染的敏感性反应。结果表明:不同pH值的酸雨对园林植物新叶片有不同程度的抑制,酸雨的酸度越大,对园林植物叶片的伤害越大,以pH值1.7的模拟酸雨对园林植物叶片的伤害最为严重,pH值5.6伤害较为轻微,但不同种类之间对酸雨的抗性有明显差异;pH值4.3~5.6处理对园林植物新梢生长率没有显著的影响和抑制作用,而pH值小于3.0处理则严重抑制了园林植物新梢生长;随模拟酸雨强度的增强,园林植物叶片的细胞质膜透性和丙二醛(MDA)含量逐渐升高,当pH值小于3.0时,细胞质膜透性和丙二醛(MDA)含量则急剧增加,当pH值为1.7时,不同园林植物叶片则严重受损;园林植物叶片叶绿素含量、叶片N和P含量随酸雨强度的增加逐渐降低,当pH值小于3.0时,园林植物叶片叶绿素含量、叶片N和P含量则急剧降低,当pH值为1.7时,不同园林植物叶片则严重受损;相关分析表明,酸雨增加了园林植物对环境的敏感性。园林植物对酸雨具有较强的抵抗能力,对园林植物生理活动影响的阈值pH值大致介于3.0~4.3,因此,本研究的6种园林植物可以作为酸雨灾害严重地区园林绿化及植被构建的物种。  相似文献   

15.
Eugenia uniflora and Clusia hilariana seedlings were submitted to simulated acid rain, pH 3, for 40 days. The degree of visible injury and the anatomical and micromorphological alterations were determined 24 hours after the last simulation. E. uniflora presented a higher degree of leaf necrosis. The adaxial epidermis and part of the palisade parenchyma of the entire leaf blade were affected and hypertrophy, hyperplasia and cicatrization tissue differentiation occurred. Erosion and morphological modification of the epicuticular wax and alterations in the epidermis were detected on the upper and lower leaf surfaces. Stomata with deformed ostioles and rupture of the stomatal ledge were observed. C. hilariana presented necrosis in leaf margin and in abaxial leaf surface, showing collapsed cells or with plasmolized aspect, cicatrization tissue, epicuticular wax alterations, occasional leaf perforations, irregular arrangement of adaxial epidermis cells and twisted subsidiary cells. The structural alterations indicated a greater susceptibility of E. uniflora to acid rain. he lower sensibility of C. hilariana can be related with the anatomical characteristics as: thick cuticle with evident cuticular flanges, three layers of hypodermis and mesophyll more thick and compact.  相似文献   

16.
Wind-blown rain, rain splash, and films of free moisture play important roles in the epidemiology of many plant diseases. The effects of simulated rain acidified with sulfuric acid were studied on several host-parasite systems. Plants were exposed in greenhouse or field to simulated rain of pH 3.2 ± 0.1 or pH 6.0 ± 0.2. Simulated ‘rain’ of pH 3.2 resulted in: (1) an 86% inhibition in telia production of Cronartium fusiforme on Quercus phellos; (2) a 66% inhibition of reproduction of Meloidogyne hapla on field-grown Phaseolus vulgaris; (3) a 10% decrease in the severity of Uromyces phaseoli on field-grown Phaseolus vulgaris; and (4) an inhibition of Rhizobium nodulation of Phaseolus vulgaris and Glycine max by an average of 73%. Effects on halo blight of kidney bean (caused by Pseudomonas phaseolicola) depended upon the segment of the disease cycle in which the ‘rain’ occurred: (a) simulated rain of pH 3.2 applied to plants before inoculation stimulated disease development; (b) suspension of inoculum in ‘rain’ of pH 3.2 decreased inoculum potential; and (c) ‘rain’ of pH 3.2 applied to plants after infection inhibited disease development. Scanning electron microscopy of epicuticular waxes on leaves of Quercus phellos and Phaseolus vulgaris showed marked erosion of those surfaces by ‘rain’ of pH 3.2, indicating possible influences on the structure and function of plant cuticles. These results suggest that the acidity of rain is a new parameter of environmental concern, and underline the need for study of the consequences of prolonged exposure of both agronomic and natural ecosystems to this stress factor.  相似文献   

17.
酸雨对木芙蓉幼苗光合作用及抗氧化酶活性的影响   总被引:2,自引:0,他引:2  
王应军  邓仕槐  姜静  尚鹤  林波  孙亚琴  胡晓梅 《核农学报》2011,25(3):588-593,581
以pH 5.6为对照,采用pH 4.0、pH 3.0、pH 2.0强度的酸雨对2年生木芙蓉进行人工模拟胁迫,研究酸雨胁迫对木芙蓉叶片可见伤害、质膜透性(Membrane Permeability,MP)、叶绿素(Chlorophyll,Chl)含量、抗氧化酶系统及气体交换参数的影响.研究结果表明,pH 2.0和pH 3...  相似文献   

18.
In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H2SO4 and nitrate, and rain water containing ammonium sulphate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulphate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulphate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH=3.8. Under acidified conditions, ammonium sulphate deposition lead to a luxuriant growth ofJuncus bulbosus andAgrostis canina. In the mini-ecosystems, H2SO4 deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr. The acidification of water appeared to be coupled with changes in alkalinity, sulphate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH3-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulphate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters.  相似文献   

19.
Physiological processes in field-grown soybean (Glycine max L. Merr. 'Davis’) to determine if plant responses were altered by simulated acid rain and if the responses to acid rain were modified by the presence of gaseous pollutants. Applications of simulated acid rain (pH 3.2, 4.2, and 5.2), alone or in combination with gaseous pollutants, did not significantly affect photosynthesis, transpiration, stomatal conductance of water vapor, or chlorophyll content at periodic intervals during the 1984 season. Furthermore, in leaf samples collected during pod fill, the concentrations of 11 elements were not significantly affected by simulated acid rain, alone or in combination with gaseous pollutants. These data are evidence that combinations of ambient rain and gaseous pollutants at similar levels may not cause significant physiological disruption in field-grown Davis soybean, and provide mechanistic support for studies where no significant effects on yield were reported.  相似文献   

20.
Lichens of the genus Peltigera were exposed to simulated acid rain in the laboratory and at a field site in Southwestern Alaska. Exposure to simulated rainfall of pH 4.4 had no effect upon acetylene reduction in P. rufescens after experiments of 28 and 60 days duration, although in the former experiment there was some evidence of a transient effect after 14 days. Simulated acid rain of pH 3.4 or 4.4 also had no effect upon nitrogenase activity in P. aphthosa during a 21-day field study, indicating that nitrogenase activity in Peltigera is not sensitive to precipitation in this range of acidity.  相似文献   

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