Mineral nutrition of Arnica montana L. and Arnica chamissonis ssp. foliosa maguire: Differences in the cation acquisition

The cultivation of the calcifuge Arnica montana naturally found on poor soils is important because of its pharmaceutical use. Influences of nutrient availability on the cation acquisition by the two Arnica species Arnica montana (Europe) and Arnica chamissonis (North America) were investigated in hydroponic culture. The contents of the divalent cations calcium and magnesium were higher on a dry matter basis in Arnica montana, while the quantities of the monovalent potassium were higher in Arnica chamissonis. High calcium concentrations in the medium lowered the accumulation of other cations in Arnica montana, but Arnica chamissonis was less affected. Arnica chamissonis was more susceptible to increased phosphate concentrations in the medium than Arnica montana. With 0.6 raM phosphate necrotic spots appeared on leaves of Arnica chamissonis. Arnica montana was not affected by this phosphate concentration, but the same symptoms became visible at higher phosphate levels. In both species, no major effect of the chemical form of the N‐source on cation accumulation was observed. According to these results, the two Arnica species differ in the discrimination between the monovalent (K⁺) and the divalent (Ca⁺⁺, Mg⁺⁺) cations. Arnica montana and Arnica chamissonis (two species of the same genus) should be considered as an interesting model system for the investigation of cation acquisition and discrimination.     

Response of eight tropical plants to enhanced ammonia deposition under field conditions prevalent with SO2 and NH3

The impact of SO₂ on the deposition of ammonia and the response of eight tropical tree species to excess deposition of ammonia was investigated. This was achieved by studying physiological aspects like total sugars, protein, nitrate reductace (NR) activity, organic/inorganic nitrogen ratio, specific leaf area and foliar injury in plants growing under field conditions prevalent with SO₂ and NH₃. Analysis of water soluble substances present on foliar surfaces of the trees indicated enhanced NH₄ ⁺ deposition and thereby result in enhanced foliar protein contents. Though the enhanced nitrogen was almost the same in different plants, the plants exhibited differential metabolic disturbances. Critical analysis of the results indicated three distinct types of plant response. Plants like Azadirachta indica, Acacia auriculiformis and Bambusa arundinaceae maintained enhanced total sugars and NR activity and incorporated excess NH₄ ⁺ into proteins, thus enabling the plant to compensate/alleviate SO₂ induced injury. Ficus benghalensis and Ficus religiosa maintained unaltered total sugars and NR activity and could partly incorporate NH₄ ⁺ into proteins, thus modifying the SO₂ impact to some extent. Dalbergia sissoo, Eucalyptus rostrata and Mangifera indica could not incorporate the excess NH₄ ⁺, mainly due to declined total sugars. The results indicate the ability of a plant to undergo species specific metabolic changes in order to cope with the excess nitrogen deposition, which may ultimately result in increasing or decreasing tolerance to SO₂.     

Identification and characterization of two new derivatives of chlorogenic acids in Arnica (Arnica montana L.) flowers by high-performance liquid chromatography/tandem mass spectrometry

Arnica montana is a medicinally important plant due to its broad health effects, and it is used in Ayurvedic, Homeopathic, Unani, and folk medicines. We have used LC-MS(n) (n = 2-5) to detect and characterize in Arnica flowers 11 quantitatively minor fumaric and methoxyoxalic acid-containing chlorogenic acids, nine of them not previously reported in nature. These comprise 1,5-dicaffeoyl-3-methoxyoxaloylquinic acid, 1,3-dicaffeoyl-4-methoxyoxaloylquinic acid, 3,5-dicaffeoyl-4-methoxyoxaloylquinic acid, and 1-methoxyoxaloyl-4,5-dicaffeoylquinic acid (M(r) 602); 3-caffeoyl-4-feruloyl-5-methoxyoxaloylquinic acid and 3-feruloyl-4-methoxyoxaloyl-5-caffeoylquinic acid (M(r) 616); 1,5-dicaffeoyl-4-fumaroyl and 1,5-dicaffeoyl-3-fumaroylquinic acid (M(r) 614); 3,5-dicaffeoyl-1,4-dimethoxyoxaloylquinic acid (M(r) 688); and 1-methoxyoxaloyl-3,4,5-tricaffeoylquinic acid and 1,3,4-tricaffeoyl-5-methoxyoxaloylquinic acid (M(r) 764). All of the structures have been assigned on the basis of LC-MS(n) patterns of fragmentation, relative hydrophobicity, and analogy of fragmentation patterns if compared to caffeoylquinic acids. This is the first time when fumaric acid-containing chlorogenic acids are reported in nature.     

Comparison of dry deposition velocities for SO2, HNO3 and SO4 2− estimated with two inferential models

Dry deposition velocity estimates of SO, HNO₃ and SO₄ ^2? were computed for six locations in eastern North America using two different inferential models; a Big-Leaf model utilized by the U. S. National Dry Deposition Network (NDDN) and, a land-use based model (LUM) that has been used in the past to estimate the relative importance of dry versus wet deposition over selected Canadian regions. There were consistent differences between models that were related to the surface type, chemical species and time of year. Mean monthly dry deposition velocities based upon the 1990–91 time period were compared at two locations. The seasonal cycles in deposition velocity were similar between models, but there were considerable differences in the amplitude of the cycles. The LUM predicted about a 400% increase in S042- deposition velocity from the winter to the summer months, while there was a 50 to 100% increase in the NDDN model estimates, depending upon location. According to the LUM, HN03 deposition to crop land increased by about a factor of 6 from winter to summer, while the big leaf model predicted a 50% increase. Overall, there was better agreement for SO₂. Averaged over 12 months, the differences in deposition velocity between models were smaller and generally within the range of uncertainty associated with inferential models. For all six sites, the mean percent difference between models in deposition velocity for SO₂, HNO₃ and SO₄ ^2? were 13, 35 and 79, respectively. These differences highlight the effect of using different methods for estimating dry deposition and the importance of applying the same model when examining regional patterns in dry/total deposition rates.     

NH3 and N2O Emissions after Landspreading of Slurry as Influenced by Application Technique and Dry Matter-Reduction. I. NH3 Emissions

Ammonia volatilization from slurry is undesirable because of environmental N eutrophication and loss of fertilizer value. The dry matter content of slurry, the application technique and the weather conditions are the main factors influencing NH₃ losses from landspread slurry. In a field of winter wheat a two factor plot experiment was conducted to study single and combined effects of slurry separation and application techniques, including broadcast and banded application, as well as incorporation by injection and the flexible harrow. Ammonia volatilization from all treatments could be measured simultaneously, and at ambient climatic conditions by an indirect, open measurement technique. The experiment was repeated four times. Due to varying weather conditions and treatment effects, cumulative NH₃ volatilization from the slurry during the first 48 hours ranged from 4 to 90% of total ammoniacal nitrogen (TAN). Both separation and incorporation significantly decreased NH₃ losses, but only the combination of dry matter reduction and injection or harrowing reduced NH₃ volatilization to about 30% of TAN in all weather conditions. Banding alone did not efficiently conserve slurry N, but even enhanced NH₃ volatilization in wet conditions.     

A comparison of estimated and measured SO2 deposition velocities

A nested-network program for obtaining data on the dry deposition of SO₂ and SO₄ ^? has been initiated at a small array of locations (6 in 1985, presently 13) across North America. The procedures involved rely on the availability of models for deriving dry deposition rates from observations of air concentrations and of meteorological and surface properties known to influence the deposition velocity. At a subset of locations (i.e., 3), the results obtained by this indirect method are tested by comparison against more direct methods. One of the first comparison experiments of this series was conducted at Oak Ridge in July 1985 when the fluxes determined by inferential methods were compared to those measured by eddy correlation. The results obtained suggest that initial computer routines, developed to estimate deposition velocity for SOz on a routine basis, overestimate the deposition velocity by about 20% to a mixed-species deciduous forest. The difference is possibly due to the omission of water stress as a contributing factor in the initial computer routines, but might also be associated with chemical processes at the substomatal level.     

Projections of SO2, NOx,NH3 and VOC Emissions in East Asia Up to 2030

Starting from an inventory of SO₂, NO_x, VOC and NH₃ emissions for the years 1990 and 1995 in East Asia (Japan, South and North Korea, China, Mongolia and Taiwan), the temporal development of the emissions of the four air pollutants is projected to the year 2030 based on scenarios of economic development. The projections are prepared at a regional level (prefectures or provinces of individual countries) and distinguish more than 100 source categories for each region. The emission estimates are presented with a spatial resolution of 1×1 degree longitude/latitude. First results suggest that, due to the emission control legislation taken in the region, SO₂ emissions would only grow by about 46 percent until 2030. Emissions of NO_x and VOC may increase by 95 and 65 percent, respectively, mainly driven by the expected increase in road traffic volume. Ammonia, mainly emitted from agriculture, is projected to double by 2030.     

Effect of SO2 and NH3 on growth behavior of some phylloplane fungi of wheat in in vitro

The colony growth of some phylloplane fungi of wheat viz. Alternaria alternata, Aspergillus favus, Amiger, Cladosportium cladosporioides, Curvularia lunata, Drechslera australiensis, Epicoccum purpurascens, Fusarium oxysporum, Penicillium chrysogenum and P. citrinum were studied in chamber fumigation experiments exposed to 2669 ± 105 μg SO₂ m^?3 and 708.33 ± 55 μg NH3 m^?3 air, separately, for 10, 30 and 60 min. The colony growth of all the test fungi was significantly (P=0.01/0.005) inhibited on prolonged period of SO₂/NH₃ exposure. However, some of the test fungi namely A. favus, A. niger, E. purpurascens and F. oxysporum showed growth stimulation after 10 min exposure of SO₂. Similarly, the growth of C. lunata and F. oxysporum increased only after 10 min exposure of NH3. The inhibitory effect of SO₂/NH₃ was directly correlated with the exposure times.     

Balance and immobilization of (15NH4)2SO4 in a soil after the addition of Didin as a nitrification inhibitor

Summary We studied the effect of a dicyandiamide-based nitrification inhibitor (Didin) on the kinetics of N transfer in soil. Incubation at various temperatures was carried out in the laboratory after adding ammonium sulfate labelled with ¹⁵N. Adding Didin increased the incorporation of mineral N in a form that could not be extracted by KCl. The temperature modified the incorporation kinetics, but after 1 year, no difference remained between the two treatments in which the inhibitor had been added, and in which the total N immobilized was 26% of the ¹⁵N added compared with 13% in the control treatment. Losses of ¹⁵N, measured by difference, were greater in the control treatment (approximately 14%) than in the treatments containing Didin (10%). The addition of a nitrification inhibitor did not lead to the development of denitrifying microflora, the losses being mainly attributable to volatilization of NH₃ encouraged by the high pH of the soil. The immobilized N was mainly found in the NH₄ ⁺ form, adsorbed at the beginning of the incubation and subsequently in the amino acids. It seemed that the Didin effect on microflora was indirect, arising from longer maintenance of the tracer in NH₄ ⁺ form. This hypothesis was borne out by computing the gross phenomena. The variation in results reported in the literature can therefore be attributed to modifications in immobilization kinetics.     

Impacts of (NH4)2SO4 Deposition on Norway Spruce (Picea Abies [L.] Karst) Roots

The effects of enhanced (NH₄)₂SO₄ (NS) deposition on Norway spruce (Picea abies [L.] Karst) fine root biomass, vitality and chemistry were investigated using root-free in-growth cores reproducing native organic and mineral soil horizons. The cores were covered and watered every 2 weeks with native throughfall or throughfall supplemented with NS to increase deposition by 75 kg ha^-1 a^-1 NH₄ ⁺-N (86 kg ha^-1 a^-1 SO₄2--S). The in-growth cores were sampled after 19 months and assessed for root biomass, necromass, length, tip number, tip vitality and fine root chemistry. Root biomass and fine root aluminium (Al) concentration were negatively correlated, but NS deposition had no effect on root growth or root tip vitality. NS deposition caused increased fine root nitrogen (N) concentrations in the organic horizon and increased Calcium (Ca) concentrations in the mineral horizon. Fine root biomass was higher in the organic horizon, where fine root Al and potassium (K) concentrations were lower and Ca concentrations higher than in the mineral horizon. Results highlighted the importance of soil stratification on fine root growth and chemical composition.     

Combined effects of nitrogen deposition and biochar application on emissions of N2O,CO2 and NH3 from agricultural and forest soils

Abstract

Both nitrogen (N) deposition and biochar can affect the emissions of nitrous oxide (N₂O), carbon dioxide (CO₂) and ammonia (NH₃) from different soils. Here, we have established a simulated wet N deposition experiment to investigate the effects of N deposition and biochar addition on N₂O and CO₂ emissions and NH₃ volatilization from agricultural and forest soils. Repacked soil columns were subjected to six N deposition events over a 1-year period. N was applied at rates of 0 (N0), 60 (N60), and 120 (N120) kg Nh a^?1 yr^?1 without or with biochar (0 and 30 t ha^?1 yr^?1). For agricultural soil, adding N increased cumulative N₂O emissions by 29.8% and 99.1% (p < 0.05) from the N60 and N120 treatments, respectively as compared to without N treatments, and N120 emitted 53.4% more (p < 0.05) N₂O than the N60 treatment; NH₃ volatilization increased by 33.6% and 91.9% (p < 0.05) from the N60 and N120 treatments, respectively, as compared to without N treatments, and N120 emitted 43.6% more (p < 0.05) NH₃ than N60; cumulative CO₂ emissions were not influenced by N addition. For forest soil, adding N significantly increased cumulative N₂O emissions by 141.2% (p < 0.05) and 323.0% (p < 0.05) from N60 and N120 treatments, respectively, as compared to without N treatments, and N120 emitted 75.4% more (p < 0.05) N₂O than N60; NH₃ volatilization increased by 39.0% (p < 0.05) and 56.1% (p < 0.05) from the N60 and N120 treatments, respectively, as compared to without N treatments, and there was no obvious difference between N120 and N60 treatments; cumulative CO₂ emissions were not influenced by N addition. Biochar amendment significantly (p < 0.05) decreased cumulative N₂O emissions by 20.2% and 25.5% from agricultural and forest soils, respectively, and increased CO₂ emissions slightly by 7.2% and NH₃ volatilization obviously by 21.0% in the agricultural soil, while significantly decreasing CO₂ emissions by 31.5% and NH₃ volatilization by 22.5% in the forest soil. These results suggest that N deposition would strengthen N₂O and NH₃ emissions and have no effect on CO₂ emissions in both soils, and treatments receiving the higher N rate at N120 emitted obviously more N₂O and NH₃ than the lower rate at N60. Under the simulated N deposition circumstances, biochar incorporation suppressed N₂O emissions in both soils, and produced contrasting effects on CO₂ and NH₃ emissions, being enhanced in the agricultural soil while suppressed in the forest soil.     

木瓜蛋白酶在PEG/PEG-IDA-Fe3+/(NH4)2SO4亲和双水相中的分配系数模型

为预测木瓜蛋白酶在PEG/PEG-IDA-Fe3+/(NH4)2SO4亲和双水相中的分配行为,在298.15K条件下利用浊点法测定并比较了PEG/(NH4)2SO4和PEG/PEG-IDA-Fe3+/(NH4)2SO4的三角相图,建立了木瓜蛋白酶在无亲和配基双水相和含亲和配基双水相中分配模型。考察双水相各组分浓度与木瓜蛋白酶在该体系中分配系数的相关度,基于酶分配系数与双水相中上下相组分浓度差之间较高相关度,提出了木瓜蛋白酶在PEG/(NH4)2SO4双水相中分配系数与上下相组分浓度差的关联模型,模型相对偏差为7.02%。引入亲和配基浓度对酶分配系数的影响因子η,提出了木瓜蛋白酶在PEG/PEG-IDA-Fe3+/(NH4)2SO4亲和双水相中分配系数模型,试验验证,预测值和试验值之间相对误差均在15%以内,能实现亲和双水相中酶的准确预测。研究结果为木瓜蛋白酶在双水相中分配系数的工程计算提供参考。     

Solute fluxes and sulfur cycling in forested catchments in SW Germany as influenced by experimental (NH4)2SO4 treatments

Results are presented from the research project Arinus which investigates biogeochemical cycling in Norway spruce (Picea abies KARST.) ecosystems in the Black Forest (SW Germany) and effects of experimental (NH_{4 2}SO₄ additions. The interaction of the terrestrial and aquatic system is assessed using an integrated approach which combines flux measurements in representative plots on the stand level with input-output budgets of small catchments. The approach, field installations and experimental manipulations are described. Results from element flux measurements in the untreated systems are presented and processes controlling N and S transformations are discussed for two catchments representing contrasting site conditions. Even though the S budget is negative for both systems there is a distinct difference in the relation between organicvs. inorganic S fractions in the soil. Sulfate mineralization and desorption, respectively are discussed as controlling processes. Sulfate retention is not only a function of soil properties, but also of water fluxes and pathways. The uptake of added SO ₄ ^2? was highly controlled by the counter-cation. Microbial N retention in the soil was highly influenced by the site management history. The extent of streamwater acidification was highly dependent on the transformations and mobility of N and S in the soils which in turn controlled cation leaching and alkalinity.     

The possible role of organic acids as allelochemicals in Tamarindus indica L. leaves

Tamarindus indica L. is well known for its acidic nature and allelopathic potential, but to date, little is known about its organic acids playing their role as allelochemicals. Hence, in the present study, identification, quantification, and contribution of organic acids present in its leaf extract were conducted using the principle of bioassay-guided procedure. High pressure liquid chromatography identified four organic acids, viz. citric, malic, oxalic, and tartaric acids, in its leaf aqueous extract with the predominance of oxalic acid (7.5 g kg^?1 leaves fresh weight) followed by tartaric acid (7.3 g kg^?1). The allelopathic activity of identified acids and aqueous extract was evaluated on lettuce seedlings growth based on the specific activity (EC₅₀). The crude extract reduced radicle growth more adversely than hypocotyl at the concentration of 2.5 g L^?1 (EC₅₀). It hindered the normal physiological growth process through weak and curly seedlings, and necrosis of their tips. Among the identified acids, oxalic acid had the highest specific activity (40 mg L^?1) and citric acid had the lowest (>1000 mg L^?1). As a consequence of its high contents, the total activity, a function of specific activity and concentration, of oxalic acid (188) was found higher followed by tartaric acid (146). The contribution of both acids influencing the specific activity of the crude extract was then turned out to be 74%. To the best of our knowledge, this is the first report identifying the oxalic and tartaric acids as growth inhibitors in tamarind leaves and quantifying their contribution in its allelopathic expression. Based on the total activity, the results suggested that oxalic and tartaric acids are the major allelochemicals in tamarind leaves. The allelopathic potential of these acids might promote the development of natural herbicides as an alternative to the synthetic ones in a most sustainable manner.     

The calculation of transboundary and deposition fluxes of SO2 and sulfate by means of aircraft measurements

Aircraft measurements of the air pollutants SO₂ and sulfate (SO_x is defined as SO₂ plus sulfate), plus data on wind velocity, wind direction and depth of the planetary boundary layer, enable the calculation of transboundary mass fluxes of SO_x. When emission data are available, an emission-deposition balance of SO_x can be determined. The results of a measurement flight, carried out on 12 February, 1986, are presented. Two tracks were flown, along the eastern and along the western border of the Netherlands, respectively. The wind was easterly. The calculated deposition flux of SO_x is converted to an area-averaged dry deposition velocity (ν _d ). The result, ν _d = 1.2 × 10^?2 m s^?1, seems to be in good agreement with literature data.     

A short-term microcosm evaluation of CO2 evolution from litter and soil as influenced by SO2 AND SO4 additions

A total of 82 samples of wet and total deposition were sampled near the limestone cathedral at Mechelen, Belgium, which is presently being affected seriously by air pollution, and at a reference site. Most of these samples were analyzed for 10 major and 7 trace ions in solution and for 15 elements in suspension. It appeared that calcite, released from the building, effectively neutralizes the rainwater in the near vicinity and produces high Ca and bicarbonate concentrations. Heavy metal concentrations are hardly affected by the building.     

Laboratory study of SO2 dry deposition on limestone and marble: Effects of humidity and surface variables

The dry deposition of gaseous air pollutants on stone and other materials is influenced by atmospheric processes and the chemical characteristics of the deposited gas species and of the specific receptor material. Previous studies have shown that relative humidity, surface moisture, and acid buffering capability of the receptor surface are very important factors. To better quantify this behavior, a special recirculating wind tunnel/environmental chamber was constructed, in which wind speed, turbulence, air temperature, relative humidity, and concentrations of several pollutants (SO₂, O₃, nitrogen oxides) can be held constant. An airfoil sample holder holds up to eight stone samples (3.8 cm in diameter and 1 cm thick) in nearly identical exposure conditions. SO₂ deposition on limestone was found to increase exponentially with increasing relative humidity (RH). Marble behaves similarly, but with a much lower deposition rate. Trends indicate there is little deposition below 20% RH on clean limestone and below 60% RH on clean marble. This large difference is due to the limestone's greater porosity, surface roughness, and effective surface area. These results indicate surface variables generally limit SO₂ deposition below about 70% RH on limestone and below at least 95% RH on marble. Aerodynamic variables generally limit deposition at higher relative humidity or when the surface is wet.     

Dry deposition velocity estimates of SO2 from models and measurements over a deciduous forest in winter

Measurements were made of concentrations and vertical flux densities (using the eddy correlation technique) for SO₂ over a deciduous forest during March and April 1990. These were compared with estimates of dry deposition velocities, obtained from resistance analogue models that employ measured meteorological data as input. The models include: (1) the dry deposition module that forms part of a larger Eulerian air quality model, known as ADOM (Acid Deposition and Oxidant Model), (2) a modified version of ADOM and (3) a new parameterization for R _c . The observations yielded V _d values of about 0.5 cm s^?1 for the daytime and 0.1 cm s^?1 at night. ADOM's estimates were much larger, averaging about 3.0 cm s^?1 during the daytime and about 2.0 cm s^?1 at night. When the ADOM canopy resistance was increased by modifying its formulation, the modified dry deposition estimates were slightly larger during the day than at night, averaging about 0.5 cm s^?1. The new parameterization for R _c yielded smaller V _d estimates with no diurnal variation. An attempt is made to relate the observed diurnal cycle of the dry deposition velocity to meteorological parameters.     

Concentrations and depositions of SO2, SO4 2− etc. in a Chongqing suburban forested area

During the period from 25 May 1991 to 30 May 1992 the atmospheric concentrations and depositions of oxides of sulfur were continuously measured in a suburban masson pine forest which is currently experiencing severe dieback, in Chongqing, China. The annual mean concentrations of SO₂ and particulate SO₄ ^2? were 220 μ g/m³ (77 ppbv) and 32 μ g/m³ respectively. The atmospheric concentrations of these sulfur compounds were high in late autumn and winter. The annual wet and dry depositions of sulfur to the forest as measured by throughfall and stemflow were 93.1 and 46.6 kgSha^?1a^?1 respectively. These depositions are among the highest level ever reported in the world. Althogh the cause of the dieback of the masson pine trees has not been unequivocally determined, it is probable that the direct impact of SO₂ is more likely the cause than acid deposition.     

Impact of sulfate nutrition on the utilization of atmospheric SO2 as sulfur source for Chinese cabbage

The ability of Chinese cabbage (Brassica pekinensis) to utilize atmospheric sulfur dioxide (SO₂) as sulfur (S) source for growth was investigated in relation to root sulfate (SO ) nutrition. If seedlings of Chinese cabbage were transferred to a sulfate‐deprived nutrient solution directly after germination, plants became rapidly S‐deficient. Plant‐biomass production was decreased and the shoot‐to‐root ratio decreased. Sulfate deprivation resulted in a substantial decrease in total S, sulfate, organic‐S, and water‐soluble nonprotein thiol contents and in an increase in amino‐acid content of both shoot and root. The sulfate‐uptake rate of the root was strongly increased, whereas nitrate‐uptake rate was decreased. Upon resupply of sulfate, the onset of S‐deficiency symptoms was prevented, and growth was restored, whereas sulfate and nitrate‐uptake rates were quite similar to those of the sulfate‐sufficient plants. A 6‐day exposure to 0.12 µL L^–1 SO₂ of sulfate‐sufficient plants did not affect plant‐biomass production, shoot‐to‐root ratio, S and nitrogen (N) compounds of shoot and root, or sulfate and nitrate uptake by the root. Exposure of sulfate‐deprived plants to SO₂ resulted in enhanced total S, organic‐S, and water‐soluble nonprotein thiol contents of the shoot. The contribution of SO₂ as S source for biomass production depended on the duration of the sulfate deprivation. If Chinese cabbage was transferred to a sulfate‐deprived nutrient solution and simultaneously exposed to SO₂, then plants benefited optimally from the foliarly absorbed S. The development of S‐deficiency symptoms was prevented, and shoot‐biomass production was quite similar to that of sulfate‐sufficient plants. However, upon SO₂ exposure root‐biomass production was even higher than that of sulfate‐sufficient plants, whereas sulfate uptake was still enhanced. Evidently, upon SO₂ exposure there was no strict and direct shoot‐to‐root signaling in tuning sulfate uptake by the root and its transport to the shoot to the need for growth, via down‐regulation of sulfate uptake and normalizing shoot–to–root biomass partitioning.