Responses of bean (Phaseolus vulgaris L. cv. Pros) to chronic ozone exposure at two levels of atmospheric ammonia

Plants of bean (Phaseolus vulgaris cv. Pros) were exposed to a range of O3 concentrations up to 70 nl litre(-1) for 9 h day(-1) in the presence (45 nl litre(-1)) and absence (21 nl litre(-1)) of enhanced NH3 in 12 open-top chambers. Treatment effects on visible injury, growth and yield were assessed after 49 (intermediate harvest) and 62 days of exposure (final harvest). The proportion of leaves with visible injury at final harvest increased with increasing concentrations of O3. Enhanced NH3 did not cause any symptoms and did not affect injury by O3. The estimated seasonal mean concentration corresponding with 5% injury was circa 23 nl litre(-1) O3. Biomass production and green pod yield decreased with increasing concentrations of O3 and were generally stimulated by enhanced NH3 at both harvests. Adverse effects of O3 on biomass and pod yield did not depend on the NH3 level. Relative yield response to increasing 9-h daily mean O3 concentrations was nonlinear and yield losses of 5 and 10% were calculated to occur at seasonal daytime mean concentrations of 27 and 33 nl litre(-1) O3, respectively. Linear regression showed that the Accumulated exposures Over a Threshold of 30 (AOT30) and 40 nl litre(-1) (AOT40) O3 performed equally well. The estimated accumulated O3 exposures corresponding with a yield loss of 5% were 1600 nl litre(-1) h for AOT30 and 400 nl litre(-1) h for AOT40. The results are discussed in relation to the long-term critical level that is used as a guideline to protect crops against adverse effects by O3.     

Effects of various ozone exposures on the susceptibility of bean leaves (Phaseolus vulgaris L.) to Botrytis cinerea

The effects of various ozone exposures in predisposing bean leaves (Phaseolus vulgaris L.) to Botrytis cinerea have been investigated under laboratory conditions. Seedlings of two bean cultivars were exposed to incremental ozone concentrations (120, 180 and 270 microg m(-3) for 8-h day(-1)) for five days and primary leaves were subsequently inoculated with conidia suspended in water or in an inorganic phosphate solution (Pi), and with mycelium. Ozone injury increased with increasing ozone concentration and was much higher in the ozone-sensitive cultivar 'Pros' than in the ozone-insensitive 'Groffy'. Ozone only increased the number of lesions on leaves of Pros after inoculation with either of the conidial suspensions. The Pi-stimulated infection in Groffy was reduced by the lower ozone concentrations. Ozone decreased lesion expansion after inoculation with mycelium. In a chronic fumigation experiment, plants of the two cultivars were exposed to 90 microg m(-3) (7-h day(-1)) and the primary and the oldest tree trifoliate leaves were inoculated after five and seven weeks of exposure. Ozone enhanced the senescence-related injury only in Pros. The number of lesions was not influenced by ozone for either cultivar, conidial suspension or inoculation date. Lesion expansion after inoculation with mycelium was generally reduced in exposed plants. Thus, contrasting effects of ozone on the susceptibility of bean leaves to B. cinerea were observed depending on the cultivar, the conidial suspension, the disease parameter and the ozone exposure pattern. In extrapolating the laboratory results to the field, it is suggested that episodic and chronic exposures to ambient ozone are of minor importance in increasing the susceptibility of bean leaves to B. cinerea.     

Inheritance of ambient ozone insensitivity in common bean (Phaseolus vulgaris L.)

The inheritance of ozone (O(3)) insensitivity in common bean (Phaseolus vulgaris L.) was evaluated using F(2) and F(3) populations under ambient conditions. This study was conducted over two growing seasons (1987, 1988) at Virginia State University, Randolph Research Farm, Petersburg, Virginia. Two populations were obtained by crossing insensitive plant introductions with sensitive commercial cultivars. Ratings on the scale of 1 to 5 (1 = 0 to 20% leaf injury, 2 = 21 to 40%, 3 = 41 to 60%, 4 = 61 to 80%, and 5 > 80%) were made on 160 F(2), F(3) progenies, and parental lines. Population mean injury ratings were recorded and estimates of genotypic, environmental, and phenotypic variances were computed. Estimates of heritability in the broadsense and of genetic advance were calculated for each population using F(2) and family component variance methods. Population means of the F(2) and F(3) progenies were not significantly different from their mid-parent values, suggesting that genetic variance was primarily additive. Broad-sense heritability estimates using F(2) variance method ranged from 51.4 to 70.5% and using family component variance method ranged from 62.1 to 75.6%. In this study, the computed genetic advance values closely parallel those of heritability estimated values. The high heritable nature of insensitivity would indicate that effective levels of insensitivity could be transferred to agronomically superior cultivars in a relatively short time.     

The effects of oil spill chemicals on carbon translocation rates in Phaseolus vulgaris L

Phaseolus vulgaris L. cv. Black Valentine when sprayed with Corexit dispersants shows a rapid inhibition of photosynthesis. The plant retains the ability to translocate fixed carbon, and this involves mobilising previously fixed carbon in the sprayed leaf or the repartitioning of carbon from unsprayed regions of the plant towards the growing sink regions. The ability to maintain carbon translocation while photosynthesis is declining maximises the regrowth potential of the plant.     

Effects of ethylenediurea and ozone on the antioxidative systems in beans (Phaseolus vulgaris L.)

To study the biochemical mechanism of EDU protection against ozone injury, peroxidase, ascorbate-dependent peroxidase, and catalase activities, and the contents of ascorbic acid, dehydroascorbic acid, malondialdehyde and soluble protein were measured in Phaseolus vulgaris L. cv. Lit exposed to ozone and ethylenediurea (EDU) in open-top chambers. Plants not treated with EDU showed foliar bronzing due to ozone, while EDU-treated plants were not affected. EDU application modified the reaction of biochemical parameters to ozone. Soluble protein content was elevated by EDU. Peroxidase activity increased with ozone exposure in untreated plants only, while ascorbate-dependent peroxidase activity was lower in EDU treated plants. Catalase activity decreased in EDU-untreated plants. The ratio of ascorbic acid to dehydroascorbic acid was significantly increased in EDU treated plants. These results suggest that EDU might induce ascorbic acid synthesis and therefore provide the plant with a very potent antioxidant. Or the content of hydrogen peroxide was reduced due to other unknown processes and caused a delay in foliar senescence, regardless of whether these processes were ozone-induced or due to natural aging processes.     

Effects of nitrogen dioxide on growth and yield of black turtle bean (Phaseolus vulgaris L.) cv. 'Domino'

Twenty-six-day-old black turtle bean cv. 'Domino' plants were exposed to nitrogen dioxide (0.0, 0.025, 0.05 and 0.10 microl liter(-1)), 7 h per day for 5 days per week for 3 weeks, under controlled environment. Data were collected on net photosynthesis rate (PN), stomatal resistance (SR), and dark respiration rate (DR), immediately after exposure, 24 h after the termination of exposure and at maturity (when the leaves had just started turning yellow), using a LICOR 6000 Portable Photosynthesis System. Chlorophyll-a (Ch-a), chlorophyll-b (Ch-b), total chlorophyll (tot-Ch) and leaf nitrogen were measured immediately after exposure and at maturity. Growth characteristics-relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and root: shoot ratio (RSR)-were computed for treated plants. Net photosynthesis rate increased by 53% in 0.10 microl liter(-1) NO2 treated plants immediately after exposure compared to control plants. Dark respiration rates were also higher in treated plants. Ch-a, Ch-b and tot-Ch showed significant increases with 0.1 microl liter(-1) NO2 treatment immediately after exposure. Foliar nitrogen content showed an increase in treated plants both immediately after exposure and at maturity. Increases were also seen in RGR and NAR. Plant yield increased by 86% (number of pods), 29% (number of seeds) and 46% (weight of seeds), respectively. Nitrogen dioxide stimulated the overall plant growth and crop yield.     

Total arsenic accumulation in edible pods and seeds of Phaseolus vulgaris.

The main objective of this study was to evaluate whether arsenic accumulated in the edible pods and seeds of Phaseolus vulgaris, cv. Helda, above the Spanish maximum recommended concentration for food crops, 1 mg kg(-1) on a fresh weight basis. Only organic arsenicals were used because they are: a) the only arsenic species allowed for agricultural applications and b) more mobile than inorganic species. Selection of French beans, a sensitive plant to arsenic, was based on the fact that arsenic upward translocation is higher in sensitive than in tolerant plants. A 2 x 3 factorial experiment was conducted with two organic arsenic species: methylarsonic acid (MAA) or dimethylarsinic acid (DMAA) and three arsenic concentrations: 0.2, 0.5, or 1.0 mg L(-1). Arsenic phytotoxicity was primarily determined by soluble arsenic concentration. Experimental results showed that the low bean plant tolerance to arsenic is possibly due to the high arsenic upward transport to shoots, which could result in profound negative metabolic consequences. Even under extremely adverse conditions, arsenic residues in edible beans were below the maximum statutory limit set by the Spanish legislation. It can be concluded that the major danger of organic arsenical herbicides is that of decreased productivity rather than high arsenic uptake by consumers.     

Deposition of atmospheric ammonia to moorlands

Micrometeorological methods were applied to measure fluxes of atmospheric ammonia (NH3) to moorlands. Measurements were made in a wide variety of surface conditions and included both Calluna vulgaris (L.) Hull and Eriophorum vaginatum L. dominated sites. NH3 was found to deposit rapidly to all the sites investigated, providing large deposition velocities (Vd, typically 10-40 mm s(-1)) and usually minimal surface resistances (rc). A small number of measurements were made in frozen conditions and suggest a possible exception to this pattern with mean rc of 50-200 s m(-1). The effect of vegetation drying was also investigated and a possible increase in rc observed, though this was small (< 10 s m(-1)). The results are interpreted in terms of the processes controlling exchange; it is shown that NH3 deposition is predominantly to the leaf surfaces and that the net NH3 compensation point approaches zero. Annual estimates show that dry deposition of NH3 is a major source of atmospheric nitrogen to moorland ecosystems. For two typical UK sites subject to background air concentrations, NH3 dry deposition is of similar magnitude to equivalent NH4+ inputs in wet deposition. In the vicinity of emission sources, NH3 dry deposition is expected to dominate inputs of atmospheric nitrogen.     

Injury response of Phaseolus vulgaris to ozone flux density

This study describes a quantitative relationship between mean O₃ flux density and the length of exposure needed for the occurrence of visual injury to Phaseolus vulgaris L. Similar relationships were found for 14 day old and 6 week old plants using a whole leaf gas exchange cuvette system. Cultivars Seafarer (O₃ sensitive) and Gold Crop (O₃ resistant) exhibited similar responses at flux densities > 3 mg m⁻² h⁻¹ but only Seafarer was injured below this flux density. O₃ concentration and length of exposure period alone did not contain sufficient information to describe the onset of visual foliar injury. The use of O₃ concentrations in excess of normal ambient conditions compensated for low leaf conductances so that flux densities in the cuvette were similar to those found in the field.     

Effects of atmospheric ammonia on vegetation--a review

Atmospheric ammonia does not only cause acute injuries at vegetation close to the source, but significantly contributes to large scale nitrogen eutrophication and acidification of ecosystems because the amount of sources is high and after conversion to ammonium it can reach remote areas by long-range atmospheric transport. Besides having acute toxic potential, NH(3) and NH(4)(+) (= NH(y)) may disturb vegetation by secondary metabolic changes due to increased NH(y) uptake and assimilation leading to higher susceptibility to abiotic (drought, frost) and biotic (pests) stress. Prevention of damage to natural and semi-natural ecosystems will only be achieved if NH(3) emissions are drastically reduced. In this paper, the current knowledge on NH(y) emission, deposition, and its effects on vegetation and ecosystems are reviewed. Critical levels and critical loads for nitrogen deposition are discussed.     

The rapid inhibition of root respiration after exposure of bean (Phaseolus vulgaris L.) plants to ozone

The metabolic activity of the roots was very sensitive to the changes induced in the leaves by O₃. Respiratory activity began to decrease well before visible injury appeared on the leaves, and the per cent reduction of respiration was much greater than the per cent leaf injury. The triphenyl tetrazolium chloride (TTC) staining technique revealed changes in root tips very quickly, was generally more sensitive to changes in respiratory activity and was a convenient technique for handling large numbers of samples. Reducing foliar injury from O₃ with low levels of SO₂ reduced the effects on the roots indicating the effect of O₃ is on processes in the leaf.     

The uptake of elemental iodine vapour by bean leaves

Deposition of iodine vapour to leaves of phaseolus vulgaris was measured over a range of conditions of humidity, temperature and illumination. Transpiration measurements were used to deduce stomatal opening. The results showed that stomatal resistance controlled iodine absorption at relative humidities below 40 per cent, but that the rate of absorption of iodine increased by an order of magnitude when the relative humidity was raised to 80 per cent, presumably due to cuticular absorption. After exposure to iodine at high humidity, a substantial fraction of the iodine could be washed from the leaves. In Britain, cuticular uptake would probably dominate stomatal uptake of iodine on most occasions.     

Olive tree, Olea europaea L., leaves as a bioindicator of atmospheric PCB contamination

Olive tree leaf samples were collected to investigate their possible use for biomonitoring of lipophilic toxic substances. The samples were analyzed for 28 polychlorinated biphenyls (PCB) congeners. Twelve congeners were detected in the samples. PCB-60, 77, 81, 89, 105, 114, and 153 were the most frequently detected congeners ranging from 32 % for PCB-52 to 97 % for PCB-81. Σ₁₂PCBs concentration varied from below detection limit to 248 ng/g wet weight in the sampling area, while the mean congener concentrations ranged from 0.06 ng/g (PCB-128?+?167) to 64.2 ng/g wet weight (PCB-60). Constructed concentration maps showed that olive tree leaves can be employed for the estimation of spatial distrubution of these congeners.     

Deposition of fixed atmospheric nitrogen and foliar nitrogen content of bryophytes and Calluna vulgaris (L.) Hull

Atmospheric deposition of fixed nitrogen as nitrate and ammonium in rain and by dry deposition of nitrogen dioxide, nitric acid and ammonia has increased throughout Europe during the last two decades, from 2-6 kg N ha(-1) year(-1) to 15-60 kg N ha(-1) year(-1). The nitrogen contents of bryophytes and the ericaceous shrub Calluna vulgaris have been measured at a range of sites, with the objective of showing the degree to which nitrogen deposition is reflected in foliar plant nitrogen. Tissue nitrogen concentrations of herbarium bryophyte samples and current samples of the same species collected from the same sites were compared. No significant change in tissue nitrogen was recorded at a remote site in north-west Scotland where nitrogen inputs are small (< 6 kg N ha(-1) year(-1)). Significant increases in tissue N occurred at four sites ranging from 38% in central Scotland to 63% in Cumbria where nitrogen inputs range from 15 to 30 kg N ha(-1) year(-1). The relationships found between the estimated input of atmospheric nitrogen and the tissue nitrogen content of the selected bryophytes and Calluna at the sites investigated were found to be generally linear and fitted the form N(tissue) = 0.62 + 0.022 N(dep) for bryophytes and N(tissue) = 0.83 + 0.045 N(dep) for Calluna. There was thus an increase in total tissue nitrogen of 0.02 mg g(-1) dry weight for bryophytes and 0.045 mg g(-1) dry weight for Calluna for an increase in atmospheric nitrogen deposition of 1 kg ha(-1) year(-1). The lowest concentrations were found in north-west Scotland and the highest in Cumbria and the Breckland heaths of East Anglia, both areas of high atmospheric nitrogen deposition (30-40 kg N ha(-1) year(-1)). The implications of increased tissue nitrogen content in terms of vegetation change are discussed. Changes in atmospheric nitrogen deposition with time were also examined using measured values and values inferred from tissue nitrogen content of mosses. The rate of increase in nitrogen deposition is not linear over the 90-year period, and the increases were negligible over the period 1880-1915. However, during the period 1950 to 1990 the data suggest an increase in nitrogen deposition of 2 kg N ha(-1) every 10 years.     

Diffusion scrubber technique used for measurements of atmospheric ammonia

A diffusion scrubber (DS) was developed to measure trace levels of gaseous ammonia in ambient air. The sampling resolution time for this method is 10 min and the detection limit is estimated to be 0.01 ppbv. The response to the NI-I₃ concentrations is found to be dependent on the relative humidity in the ambient air and the temperature. The method is calibrated by using a diluted NH₃ cylinder gas, and the concentrations of the calibration gas were in the range 0.02–2 ppbv during the test. Sampling performed with the DS-method is compared to sampling performed by a filter pack and a continuous flow denuder (AMANDA). The DS-method shows good agreement with the continuous flow denuder and the filter pack.     

The linear accumulation of atmospheric mercury by vegetable and grass leaves: Potential biomonitors for atmospheric mercury pollution

One question in the use of plants as biomonitors for atmospheric mercury (Hg) is to confirm the linear relationships of Hg concentrations between air and leaves. To explore the origin of Hg in the vegetable and grass leaves, open top chambers (OTCs) experiment was conducted to study the relationships of Hg concentrations between air and leaves of lettuce (Lactuca sativa L.), radish (Raphanus sativus L.), alfalfa (Medicago sativa L.) and ryegrass (Lolium perenne L.). The influence of Hg in soil on Hg accumulation in leaves was studied simultaneously by soil Hg-enriched experiment. Hg concentrations in grass and vegetable leaves and roots were measured in both experiments. Results from OTCs experiment showed that Hg concentrations in leaves of the four species were significantly positively correlated with those in air during the growth time (p?<?0.05), while results from soil Hg-enriched experiment indicated that soil-borne Hg had significant influence on Hg accumulation in the roots of each plant (p?<?0.05), and some influence on vegetable leaves (p?<?0.05), but no significant influence on Hg accumulation in grass leaves (p?>?0.05). Thus, Hg in grass leaves is mainly originated from the atmosphere, and grass leaves are more suitable as potential biomonitors for atmospheric Hg pollution. The effect detection limits (EDLs) for the leaves of alfalfa and ryegrass were 15.1 and 22.2 ng g^–1, respectively, and the biological detection limit (BDL) for alfalfa and ryegrass was 3.4 ng m^–3.     

Bioremediation model for atrazine contaminated agricultural soils using phytoremediation (using Phaseolus vulgaris L.) and a locally adapted microbial consortium

The objective of the present study was to examine a biological model under greenhouse conditions for the bioremediation of atrazine contaminated soils. The model consisted in a combination of phytoremediation (using Phaseolus vulgaris L.) and rhizopheric bio-augmentation using native Trichoderma sp., and Rhizobium sp. microorganisms that showed no inhibitory growth at 10,000 mg L^?1 of herbicide concentration. 33.3 mg of atrazine 50 g^?1 of soil of initial concentration was used and an initial inoculation of 1 × 10⁹ UFC mL^?1 of Rhizobium sp. and 1 × 10⁵ conidia mL^?1 of Trichoderma sp. were set. Four treatments were arranged: Bean + Trichoderma sp. (B+T); Bean + Rhizobium sp. (BR); Bean + Rhizobium sp. + Trichoderma sp. (B+R+T) and Bean (B). 25.51 mg of atrazine 50 g^?1 of soil (76.63%) was removed by the B+T treatment in 40 days (a = 0.050, Tukey). This last indicate that the proposed biological model and methodology developed is useful for atrazine contaminated bioremediation agricultural soils, which can contribute to reduce the effects of agrochemical abuse.     

Measurement and analysis of atmospheric ammonia emissions from anaerobic lagoons

Ammonia-nitrogen flux (NH₃-N=(14/17)NH₃) was determined from six anaerobic swine waste storage and treatment lagoons (primary, secondary, and tertiary) using the dynamic chamber system. Measurements occurred during the fall of 1998 through the early spring of 1999, and each lagoon was examined for approximately one week. Analysis of flux variation was made with respect to lagoon surface water temperature (∼15 cm below the surface), lagoon water pH, total aqueous phase NH_x(=NH₃+NH₄⁺) concentration, and total Kjeldahl nitrogen (TKN). Average lagoon temperatures (across all six lagoons) ranged from approximately 10.3 to 23.3^°C. The pH ranged in value from 6.8 to 8.1. Aqueous NH_x concentration ranged from 37 to 909 mg N l⁻¹, and TKN varied from 87 to 950 mg N l⁻¹. Fluxes were the largest at the primary lagoon in Kenansville, NC (March 1999) with an average value of 120.3 μg N m⁻² min⁻¹, and smallest at the tertiary lagoon in Rocky Mount, NC (November 1998) at 40.7 μg N m⁻² min⁻¹. Emission rates were found to be correlated with both surface lagoon water temperature and aqueous NH_x concentration. The NH₃-N flux may be modeled as ln(NH₃-N flux)=1.0788+0.0406T_L+0.0015([NH_x]) (R²=0.74), where NH₃-N flux is the ammonia flux from the lagoon surface in μg N m⁻² min⁻¹, T_L is the lagoon surface water temperature in ^°C, and [NH_x] is the total ammonia-nitrogen concentration in mg N l⁻¹.     

Effects of halone 1301 on Lepidium sativum, Petunia hybrida and Phaseolus vulgaris

Halone 1301 belongs to a group of widely used fire repellants. Although banned in several countries, the production has still not been discontinued, and thus hazards due to use or spill can be expected. The study reports on effects of the halone 1301 on three plant species frequently used for bioindication studies: Lepidium sativum (mouse-ear cress), Phaseolus vulgaris (bush bean) and Petunia hybrida. Plants were exposed to 1 ppbv of the gas in ambient air under controlled conditions for 18 days (L. sativum), and 45 days (P. vulgaris, P. hybrida), respectively. None of the plants showed visible stress symptoms. Chlorophylls in cress and petunia were unaffected whereas in beans significant changes of the photosynthetic pigments were observed. Photosynthesis and gas exchange of bean plants were monitored during the experiment, and a lowering of transpiration was noticed. In all investigated plants, protein contents declined significantly, but despite this reduction, activity of the glutathione S-transferases (GST) increased strongly in bean and petunia. The significance of this reaction as detoxification step is discussed.