Leonard H. Weinstein

Assessment of crop loss from ozone

The National Crop Loss Assessment Network (NCLAN) was set up to determine more accurately crop loss from ozone, sulfur dioxide, and nitrogen dioxide. The NCLAN consists of a group of government and nongovernment organizations cooperating in field work, crop production modeling, and economic studies to assess the immediate and long-term economic consequences of the effects of air pollution on crop production. The program will define the relationships between yields of major agricultural crops and doses of O/sub 3/, SO/sub 2/, NO/sub 2/ and their mixtures. These relationships will be used to assess the primary economic consequences of the exposure of agricultural crops to these pollutants. The program is also designed to advance the understanding of cause-effect relationships with the intent of developing simulation models. These nationally-coordinated field studies are designed to provide crop dose-response data that are as free of artifact as is currently possible using state-of-the-art technology. The basic exposure technique utilizes open-top chambers. These chambers have been well tested and permit control of gas(es) around the plant canopy, allowing specific pollution regimes to be imposed on experimental plants. (JMT)

A review of physical, chemical, and biological properties of fly ash and effects on agricultural ecosystems

Fly ash is the solid material which is carried away from the power plant boiler in the flue gas during coal combustion. The properties of fly ash may vary considerably according to several factors such as the geographical origin of the source coal, conditions during combustion, and sampling position within the power plant. A typical aggregate of fly ash from the combustion of eastern U.S. coals consists of spherical particles embedded in an amorphous matrix. Most fly ash particles are in the silt-sized range of 2-50 microns. The three major mineralogical matrices identified in fly ash are glass, mullite-quartz, and magnetic spinel. The major elemental constituents of fly ash are Si, Al, Fe, Ca, C, Mg, K, Na, S, Ti, P, and Mn. Nearly all naturally occurring elements can be found in fly ash in trace quantities. Certain trace elements, including As, Mo, Se, Cd, and Zn, are primarily associated with particle surfaces. The solubility of fly ash has been extensively investigated. Results of these investigations are largely dependent on factors specific to the extraction procedure. The most abundant species in fly ash extracts are inorganic ions derived from Ca, Na, Mg, K, Fe, S, and C. Boron is much more soluble than other trace elements in fly ash. The forms of some elements in fly ash extracts have been determined, but the species of most trace elements remain unidentified. Long-term leaching studies predict that fly ash will lose substantial amounts of soluble salts over time, but simulation models predict that the loss of trace elements from fly ash deposits through leaching will be very slow. The constituents of coal fly ash include small amounts of radioisotopes which do not appear to be hazardous. A complex mixture of organic compounds is also associated with fly ash particles. The organic compounds identified in fly ash extracts include known mutagens and carcinogens. Better methods for the extraction of organic compounds from fly ash particles must be developed before these compounds can be fully identified and quantified.(ABSTRACT TRUNCATED AT 400 WORDS)

Prevention of a plant disease by specific inhibition of fungal polyamine biosynthesis

DL-alpha-Difluoromethylornithine (DFMO), an inhibitor of the polyamine biosynthetic enzyme ornithine decarboxylase (EC 4.1.1.17), strongly retards the growth of several species of phytopathogenic fungi in vitro. Such inhibition can be completely reversed by putrescine or spermidine, confirming the essentiality of polyamines for growth of fungal hyphae. We now show that DFMO can protect bean plants (Phaseolus vulgaris Linnaeus cv. Pinto) against infection by uredospores of the bean rust fungus, Uromyces phaseoli Linnaeus, race O. Unifoliolate leaves of 10-day-old greenhouse-grown seedlings were sprayed with 400 microliter per leaf of DFMO at various concentrations in 0.01% Tween 20 at pH 7.0 before or after inoculation with uredospores of Uromyces. After 16 hr in darkness in dew chambers to facilitate spore germination, plants were transferred to the greenhouse, arranged randomly, and examined for local lesions 7 days later. All concentrations of DFMO 0.50 mM or higher gave complete protection against the pathogen; at lower concentrations, postinoculation treatments with DFMO were generally more effective than preinoculation. The appearance of lesions on plants treated with lower concentrations of DFMO was retarded 2-6 days. DFMO also confers protection on unsprayed parts of treated plants, indicating the translocation of some protective effect from sprayed areas. DL-alpha-Difluoromethylarginine, an analogous inhibitor of arginine decarboxylase (EC 4.1.1.19), which is the rate-limiting enzyme in an alternative pathway for polyamine biosynthesis in higher plants, confers no protection even at 5 mM. This emphasizes ornithine decarboxylase as the biochemical locus of choice for the prevention of plant diseases by inhibiting polyamine metabolism.

Tradescantia Bioassays as Monitoring Systems for Environmental Mutagenesis: A Review

Since the early studies on the genetic effects of chemical and physical agents, species and clones of Tradescantia have been used as experimental subjects, by virtue of a series of favorable genetic characteristics. Bearing just six pairs (2n = 12) of large, easily observable chromosomes, cells from almost every part of the plant, from the root tips to the developing pollen tube, yield excellent material for cytogenetic studies. As a consequence of the intensive use of Tradescantia in genetic studies, a series of genetic characteristics have been found that offer opportunities for the detection of agents affecting the stability of the genome. At least five such characteristics have been selected as endpoints for the establishment of assays to evaluate mutagenesis. Three of these, root-tip mitosis, pollen-tube, and microspore mitosis are essentially chromosome aberration assays, wherein one observes and evaluates the visible damage in the chromosomes. A fourth, the stamen-hair mutation assay (Trad-SHM), is a point mutation mitotic assay based on the expression of a recessive gene for flower color in heterozygous plants. The fifth assay is a cytogenetic test based on the formation of micronuclei (Trad-MCN) that result from chromosome breakage in the meiotic pollen mother cells. This article examines the characteristics and fundamentals of the Trad-MCN and the Trad-SHM assays and reviews the results obtained to date with these systems in the assessment of environmental mutagenesis.

The Accumulation of Fluorine by Plants

The accumulation and distribution of fluorine (F) in -plant leaves have been studied to better understand the response of plants to concentrations of atmospheric fluoride (F) that are similar to those found in urban or industrial areas. The results indicate that F from the air can be adsorbed to the surface of leaves as well as accumulated internally and that F in leaves can be translocated outward to the surface as well as upward to the tips. F injury and accumulation can be induced in any desired location on a gladiolus blade by restricting gas exchange of the blade, indicating that all parts of a blade are sensitive to F-induced injury. It is, therefore, suggested that the wide differences often found between plant species and varieties with respect to both susceptibility to injury and degree of F accumulation may be explained by differences in the means of accumulation, trans-location, and distribution of F. F remains in a soluble form in plant leaves and maintains the chemical properties of free, ino...

Native plant species suitable as bioindicators and biomonitors for airborne fluoride.

For 30-40 years airborne fluoride, usually in the form of HF or SiF4, was one of the most important and damaging air pollutants affecting forests, crops and natural vegetation. It is much more toxic than most other air pollutants such as O3 or SO2 because injury to the most sensitive species begins when they are exposed to a concentration below 1 ppb (ca. 0.8 microg m(-3)) for a 1- to 3-day period. The long-term threshold concentration is around 0.25-0.30 microg m(-3). Higher concentrations and longer durations of exposure induce much more rapid and extensive injury. However, there is a difference in sensitivity between the most and least sensitive species of around 2-3 orders of magnitude and most species possess a degree of resistance. Dramatic improvements in engineering technology have greatly reduced emissions but because of the high toxicity, cases of vegetation injury are still common, even in developed countries, and cases involving litigation still occur. Therefore there is a continuing need for bioindicators and biomonitoring of fluorides, so this paper reviews the subject, drawing attention to the strengths and limitations of the techniques. Visible symptoms are described and illustrated and tables of relative sensitivity are given and their limitations discussed. Finally, examples of biomonitoring in Europe and the USA are presented.

Uptake of fluoride and aluminum by plants grown in contaminated soils

Soils collected from areas at different distances from an aluminum smelter were studied to determine the soluble and labile F and soluble Al contents and availabilities to selected plants. Red maple seedlings (Acer rubrum L.) and orchard grass (Dactylis glomerata L.) were grown in pots containing the soils and after 3 mo foliar tissues were sampled and analyzed for the two elements. The soluble and labile contents of soil F as predictors of foliar F were compared.Significant decreases in soluble and labile F and soluble Al in soils were found with increasing distance from the smelter. As F levels in the soils increased, the F in the foliage of both orchard grass and maple increased. As Al in the soil increased, Al in maple foliage increased. Overall, F concentrations in plant foliage were below those considered as background. The results imply that, at least in the soils studied, the soil F content is not an important source of F to plants and therefore to herbivores in the area.Labile F values in the soils were significantly greater than soluble F at all sites, but, contrary to previous studies, soluble F was a better predictor of foliar F than was labile F.

Bioaccumulation of mercury by sphagnum moss near a municipal solid waste incinerator

Sphagnum moss (Sphagnum spp.) and Italian ryegrass (Lolium multiflorum Lam.) were used as biological monitors of atmospheric mercury around a municipal solid waste incinerator in rural New Jersey. Moss and grass samples were exposed according to standardized techniques at sixteen sites within 5 km of the incinerator. One remote site was monitored to establish background field accumulation. Duplicate and control monitors were used for quality assurance. In all cases, mercury concentrations in moss exceeded those in grass. Mercury accumulation by moss exhibited a spatial pattern consistent with a local source of pollution, considering wind and precipitation. Total mercury in moss exposed at sites within 1.7 km of the incinerator averaged 206 ppb while samples exposed at greater distances from the facility averaged 126 ppb.

Effects of hydrogen flouride and sulphur dioxide alone and in combination on several species of plants

Abstract Bean, barley and sweet corn were exposed separately to charcoal-filtered air, hydrogen fluoride (HF), sulphur dioxide (SO 2 ), and a combination of the two pollutants. In two experiments, plants were exposed to 0·0005–0·0007 mg F/m 3 (0·0006–0·0009 ppm), to 0·15 or 0·30 ppm (-·40 or 0·79 mg/m 3 ) SO 2 , and to the combined pollutants for 7 days. Lower concentrations of SO 2 were used in two other experiments, viz. 0·06 to 0·08 ppm (0·16–0·21 mg/m 3 ) and exposures were made for 27 days. When high concentrations of SO 2 were used, severe injury occurred on corn and barley leaves, and the combination of SO 2 and HF did not alter foliar symptom production. Beans were not injured by any of the the treatments. With lower concentrations of SO 2 , the foliar response of barley and corn was accentuated by the combination of SO 2 and HF. On both of the corn cultivars tested, symptoms consisted of elliptical lesions on the distal half of older leaves. In one experiment, foliar accumulation of fluoride was reduced by the combination of SO 2 and HF as compared with HF alone. Fresh and dry weight yields of plant tops were not affected by treatment in any experiment.

Metabolic effects of atmospheric fluorides on plants

Abstract The metabolic effects of atmospheric fluorides on plants are reviewed. Results of studies on the effect of the pollutant on individual enzymes in vitro , isolated plants or plant parts, enzyme activities or pool sizes of various metabolic intermediates in fumigated plants, or physiological processes such as photosynthesis or respiration in plants exposed to atmospheric fluorides are discussed. Each approach yields important information, but results must be interpreted in the light of the characteristics and limitations of the system employed.