利用冠层和叶片水平的反射光谱研究模拟酸雨对小麦的影响

通过光谱分析技术,研究了模拟酸雨（SO-42：NO-31=5：1）对小麦产量和生理特性的影响。结果表明,模拟酸雨伤害了小麦叶片的结构和功能,降低了叶绿素含量和光合速率,从而显著降低了小麦的产量,经过pH为2的酸雨处理后的小麦产量降幅达19.1%。通过对植被指数的分析可以看出,小麦冠层叶绿素含量在开花期以后逐渐降低,而旗叶的叶绿素含量则在灌浆期以后开始下降,两者的下降幅度都随着酸雨pH的下降而增大。光合速率表现出与叶绿素含量相同的变化。另外,对小麦产量与不同生育期冠层和叶片水平的植被指数的相关分析表明,灌浆期的小麦冠层水平的NDVI、mND705和WI与酸雨处理后小麦的产量显著相关。总之,利用光谱分析技术可以快速、无损伤地监测不同酸雨处理对小麦的生长和营养状况的影响。     

镧与酸雨对大豆幼苗荧光特性的复合影响

酸雨能改变土壤中稀土离子赋存状态从而影响其生物可利用性已是不争的事实。较之单一酸雨和单一稀土离子对植物的影响,研究两者复合作用对植物的影响将更接近自然环境的现实状况,能为客观评价酸雨危害及稀土农用的潜在风险提供丰富的基础数据。     

激光诱导叶绿素荧光强度与激光强度关系

为满足激光诱导叶绿素荧光无损检测技术的发展需要,该文利用反射式激光诱导叶绿素荧光光谱分析技术对黄瓜活体叶片的叶绿素荧光强度与激发光强度关系进行试验研究。通过中心波长为473和660 nm 2种激发光的4种激发强度（2.50、5.00、7.50、10.00 mW）对具有不同生理信息（叶绿素含量、叶片含水率）的黄瓜活体叶片进行荧光激发,并利用MATLAB软件对685 nm和732 nm两个峰位的荧光强度进行分析。结果显示：各峰位荧光强度与激发光强度成极显著线性关系;叶片叶绿素含量对荧光强度与激光强度关系影响显著,各峰位荧光变化梯度与叶绿素含量具有较好的线性关系,但叶片含水率却影响不大;以此研究为基础,建立了具有叶绿素含量参数的荧光强度与激发光强度关系数学模型,模型相对预测误差小于0.2%,可靠性好,能较真实准确地反映荧光强度与激发光强度的关系。     

酸雨和铅对大豆种子萌发的复合影响

关于酸雨（acid rain,AR）对植物种子萌发影响的研究,已有大量报道。但自然状态下,AR污染往往与重金属铅（Pb）等污染复合出现。因此,研究AR和Pb复合污染对植物种子萌发的复合影响,具有现实意义。本文以重要经济作物大豆（Glycine max）种子为试材,选取发芽率、发芽势、发芽指数、活力指数和异状发芽率5个参数作为考察目标,分析种子萌发对不同强度AR和Pb处理的响应规律,为在农业生产实践上科学评价AR与Pb复合污染的环境安全风险,提供借鉴。     

酸雨胁迫对大豆萌发种子糖代谢动态的影响

为了探索酸雨胁迫对大豆萌发种子糖代谢动态的影响,试验采用蒸馏水浸泡大豆种子,再以pH2.5、4.5模拟酸雨(AR)处理大豆种子,考察不同强度AR胁迫对大豆萌发种子可溶性糖、还原性糖、蔗糖、淀粉及α、β-淀粉酶含量的影响。结果表明,第1天AR组的可溶性糖含量上升,第2天明显降低,随后稳定降低;AR胁迫下的第1天-第4天,还原糖含量维持较高水平,第3天-第5天呈下降趋势;pH2.5组在第2天-第5天蔗糖含量减少;AR胁迫的第2天-第4天淀粉含量降低;总体上,AR组的α-淀粉酶活性CK,但从第5天起pH2.5组的α-淀粉酶活性CK;β-淀粉酶活性在第1天-第6天高于或接近CK,pH2.5组在第7天低于CK。糖代谢各项指标和淀粉酶活性之间的关系表明,可溶性糖、还原糖、蔗糖含量变化幅度随AR胁迫强度增大而增加,淀粉含量变化与之相反;AR组对淀粉酶活性影响是导致萌发改变的内在因素之一。     

酸雨与镉对大豆幼苗光合作用复合影响的模拟试验

采用生化分析方法、叶绿素荧光测定系统及透射电镜技术,测定不同强度酸雨与镉胁迫对大豆幼苗叶绿素含量、Hill反应速率、Mg2＋-ATPase活性、荧光参数及叶绿体结构的复合影响。结果表明,与对照相比,单一酸雨和镉作用下,各指标随胁迫强度变化趋势为叶绿素含量（Hill反应速率和Mg^2＋-ATPase活性）降低,初始荧光＂先降后增＂,最大光化学效率和最大量子产量＂先增后降＂。酸雨与镉复合作用下,叶绿素含量的变化表现为上述单一作用的相加效应,Hill反应速率、Mg^2＋-ATPase活性变化为单一作用的协同效应,荧光参数对酸雨与低（高）含量镉复合作用的响应表现为单一作用的拮抗效应（协同效应）。酸雨与镉复合作用下,叶绿体超微结构受到损伤。结合各指标变化进一步得出,叶绿体结构损伤是酸雨和镉对大豆幼苗叶绿素含量及光合光反应,乃至光合作用受抑的内在原因之一。     

基于激光诱导击穿光谱的土壤类型判别分析

为了更加全面的建立中国土壤类型系统,了解中国土壤地域差异,从而提高土地资源的利用率,以及根据土壤类型指导农业科学生产。该研究利用激光诱导击穿光谱(laser-induced breakdown spectroscopy,LIBS)技术结合化学计量学方法对土壤类型进行判别分析研究。从6种标准土壤样品出发,分析所采集6种土壤的LIBS光谱谱线特征,结合其主要成分物质(SiO2,Al2O3,Fe2O3,FeO,MgO,CaO,Na2O,K2O)的含量,针对每种主要物质选取了Si I 390.55 nm、Al I 394.40 nm、Fe I 422.74 nm、Mg I 518.36 nm、Na I 588.96 nm、Ca II 393.37 nm、K I 766.49 nm为特征分析谱线。结合所选的7条特征谱线下的300个标准土壤样品的光谱(200个为训练集,100个为预测集),对训练集光谱进行主成分分析(principal component analysis,PCA),6种土壤有明显的聚类。然后根据训练集光谱值和预先赋予土壤类型的虚拟等级值分别建立最小二乘判别分析(partial least squares discriminant analysis,PLS-DA)和最小二乘支持向量机(least-squares support vector machine,LS-SVM)判别模型,分析预测结果二者总的判别准确率分别为98%和100%。用受试者工作特征曲线(receiver operating characteristic curve,ROC)评价这2个模型的性能,结果表明LS-SVM判别模型性能优于PLS-DA模型。基于以上结果,选取不同于标准土壤的另7种不同类型土壤进行试验验证所选特征谱线和判别模型,建立7种不同类型土壤的LS-SVM预测模型,其预测准确率达100%,ROC曲线对其评价的性能很好。研究证明,LIBS技术结合化学计量学方法能够实现对土壤类型的判别分析,这为土壤质量的正确评价,土壤的整治、规划和合理利用提供理论基础。     

模拟酸雨对若干种蔬菜生长和生理性影响的研究

本研究在温室条件下模拟酸雨（ＰＨ２．５，３．０、４．０、５．６）对大白菜，番茄黄瓜四季豆和洋花萝卜幼苗植株生长和某些生理特性的影响。结果表明，ＰＨ２．５和３．０的模拟酸雨明显伤害蔬菜叶片，造成叶片细胞膜透性增加，叶绿素含量和根伤流量的减少。探讨了酸雨影响蔬菜幼苗生长和生理特性的一般规律和酸度阈值。     

镉与酸雨对大豆幼苗光合作用的复合影响

国内外关于镉（Cadmium,Cd）或酸雨（Acidrain,AR）单一污染对植物生长发育、生理、生化影响的研究已有大量报道,但自然背景下,上述污染极少单一存在,而多呈复合型,故研究二者复合污染对植物的影响具有理论价值与现实意义。光合器官将太阳光能转变为化学能的光合作用是植物生长发育的物质基础,光合效率是植物生产和作物产量高低的根本决定因素。     

酸雨与镧对大豆幼苗根系形态的影响

根系是植物重要吸收器官,其形态在一定程度上影响植物养分吸收功能。近年,国内外有较多关于酸雨或稀土单独影响植物根系的研究,但二者复合污染对植物根系的影响却鲜见报道。鉴于此,本文以重要经济作物大豆（Glycine max）幼苗为试     

Effect of simulated acid rain on the growth of soybean

Soybean seedlings (Glycine max) grown in a glasshouse were exposed to simulated acid rain using a solution of deionized water containing sulfate, nitrate and chloride in concentrations and proportions equivalent to those in ambient rain water. Plants were subjected to acid rain treatment twice a week during the growing season, for a 1 hr period at a rate of 5 mm hr^?1. When the acid rain was below pH 3.0, visible symptoms developed in the young trifoliate leaves. However, at a pH above 3.0 there was no evidence of visible leaf injury; also tissue dry weights and leaf areas were not affected even after 7 weeks of exposure. The number of root nodules in plants exposed to acid rain at pH 4.0 tended to be higher than those of control plants maintained at pH 5.6, but decreased subsequently with decreasing pH. Based on our results current ambient levels of rain acidity in Japan should not have an adverse impact on seedling growth in soybean.     

Effects of simulated rain acidified with sulfuric acid on host-parasite interactions

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.     

铬与酸雨污染对大豆种子萌发的复合影响

酸雨(AR)和重金属是对陆地生态系统有较大影响的2类污染物[1].中国西南及华南地区是继北美、欧洲后世界第三大酸雨区[2];同时我国南方地区有色金属矿分布密集,随矿产资源大量开采、冶炼,重金属污染日益严重[3].     

模拟酸雨对龙眼落果及果实品质的影响研究

试验研究模拟酸雨对 8年生龙眼落果及果实品质的影响结果表明 ,pH≤ 3 5的酸雨处理显著增加落果率 ,果实可溶性固形物、固酸比和糖酸比显著下降。pH为 2 5的酸雨处理果实出现伤斑 ,单果重和可食率显著降低。     

Soil chemical and microbial effects of simulated acid rain on clover and soft chess

Effects of simulated acid rain, comprised of HNO₃ and H₂SO₄ in the mole ratio of 3:1, at pH 5.6, 4.5, 4.0 and 3.0, were tested on the grass, soft chess (Bromus mollis L.) and on clover (Trifolium subterraneum L. var. Woogenellup) in a sandy soil of granodiorite parent material. Soft chess was grown in unfertilized soil, whereas clover was grown in both unfertilized soil and soil fertilized with NH₄NO₃ and CaSO₄·2H₂O at the rates of 224 kg ha^?1 N and 78 kg ha^?1 S. Two acid-spray irrigation periods of 31 and 26 weeks duration, each delivering 400 mm and separated by a dry period of 23 weeks, simulated typical rainfall of northern California rangeland. Plants were harvested after each of the two spray periods. There were very few deleterious effects of acid rain on plant growth or soil and microbial processes. No significant (p<0.05) effects were shown by soil microbial biomass, CO₂ production, nodules per unit weight of clover root, acetylene reduction, denitrification and nitrification potentials, or for soft chess plant weights, and N and P uptake. Mineralizable-N was unaffected also, except in one case. However, pH of soil to 10 mm depths was significantly lower in the pH 3.0 treatment after the first spray period, with a corresponding decrease in exchangeable soil Ca; these effects became significant at greater soil depth only after the second spray period. There were significant effects of acid treatments shown by clover, some of which may be advantageous. Treatments of intermediate acidity generally provided added N and S, which acted as fertilizers, and compensated for possible decreases in plant productivity attributable to acidity per se. There was also evidence of decreased P uptake in unfertilized soil at pH 3. In conclusion, effects of simulated acid rain were minimal, and in some cases were advantageous because of the added N and S having a fertilizer effect on plant nutrition and growth.     

Physiological responses of soybean (Glycine max L. Merr) to simulated acid rain and ambient ozone in the field

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.     

Throughfall and plant nutrient concentration response to simulated acid rain treatment

Over a 30-mo period forest microcosms were used to evaluate the impact of simulated acidic precipitation pH treatments of 5.7, 4.5, 4.0, and 3.5 annual average on the nutrient content of three tree species growing in the microcosm as well as the throughfall passing through the forest canopy. Throughfall pH responded significantly to the pH treatment and it was observed that while there was some neutralizing capacity in the canopy, it was not sufficient to completely ameliorate the treatments applied. Concentrations of Ca, Cl, and PO₄ increased in throughfall; however, these increases were generally associated with the lowest pH treatments. The principal anions, NO₃ and SO₄, introduced into the system by the precipitation treatments, exhibited different response patterns with throughfall NO₃ concentration declining with time and SO₄ increasing. While throughfall analysis suggested an increase in foliar leaching of certain elements, foliage, stem, and root analysis failed to suggest any consistently significant response for any element or tree species evaluated. Leaching of dry deposited materials and compensatory nutrient cycling are suggested as possible explanations for the observed increases in throughfall concentration in the absence of reductions in plant tissue concentrations.     

酸雨对土壤有机碳氮潜在矿化的影响

Acid rain is a serious environmental problem worldwide. In this study, a pot experiment using forest soils planted with the seedlings of four woody species was performed with weekly treatments of pH 4.40, 4.00, 3.52, and 3.05 simulated acid rain （SAR） for 42 months compared to a control ofpH 5.00 lake water. The cumulative amounts of C and N mineralization in the five treated soils were determined after incubation at 25 ℃ for 65 d to examine the effects of SAR treatments. For all five treatments, cumulative CO2-C production ranged from 20.24 to 27.81 mg kg^-1 dry soil, net production of available N from 17.37 to 48.95 mg kg^-1 dry soil, and net production of NO3-N from 9.09 to 46.23 mg kg^-1 dry soil. SAR treatments generally enhanced the emission of CO2-C from the soils; however, SAR with pH 3.05 inhibited the emission. SAR treatments decreased the net production of available N and NO3-N. The cumulative CH4 and N2O productions from the soils increased with increasing amount of simulated acid rain. The cumulative CO2-C production and the net production of available N of the soil under Acmena acuminatissima were significantly higher （P 〈 0.05） than those under Schima superba and Cryptocarya concinna. The mineralization of soil organic C was related to the contents of soil organic C and N, but was not related to soil pH. However, the overall effect of acid rain on the storage of soil organic matter and the cycling of important nutrients depended on the amount of acid deposition and the types of forests.     

Effect of simulated acid rain on mycorrhizal infection of Pinus strobus L.

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.     

Soil nutrient leaching in response to simulated acid rain treatment

Soil and soil solution nutrient concentrations were evaluated over a 30-mo period to determine the impact of simulated acidic precipitation (70:30 equivalent basis H₂SO₄: HNO₃) at pH values of 5.7, 4.5, 4.0, and 3.5 on forest. microcosms. Soil nutrient analysis indicated significantly lower concentrations of exchangeable Ca and Mg in the top 3.5 cm of the mineral soil after 30 mo of pH 3.5 treatment. Leachate collected from the pH 4.5, 4.0, and 3.5 treatments at the 25 cm depth (below the Å.: horizon) exhibited significant increases in Cl, NH₄, PO₄, K, and SO₄ concentrations compared to the pH 5.7 treatment. At the 50 cm depth (mid-profile) all leachate element concentrations except NH₄ increased significantly in response to treatment. At the 100 cm depth (profile bottom), no significant effects of treatment on leachate chemistry were observed. The elevated base cation concentration values found in the 50 cm soil solution samples support at least partially the described reduction in Ca and Mg in the surface soil horizon. The 100 cm concentration data indicate that cations mobilized out of the Å.: and upper B horizon in response to treatment were immobilized before reaching the bottom of the soil profile. Evaluation of nutrient flux out of the microcosm at the 100 cm depth did not indicate any statistically significant response to the treatment. Nitrate rather than SO₄ was found to be the dominant anion leaving the microcosm by an average factor of ～7 to 1.