Eileen Brennan

The effect of ambient ozone pollution and acidic rain on the growth and chlorophyll content of green and white ash.

Two- and three-year old green ash (Fraxinus americana L.) and white ash (Fraxinus pennsylvanica Marsh.) seedlings were exposed to combinations of ambient ozone and acidic ambient rainfall in New Brunswick, New Jersey. During the 3-year study the potted seedlings did not develop typical foliar ozone toxicity symptoms, despite the occurrence of as many as 78 h in exceedance of the National Ambient Air Quality Standard of 0.12 ppm. Although the pH of the rainfall was as low as 3.6 and averaged 4.1, no symptoms were observed resulting from the ambient precipitation. The rate of shoot growth in terms of height and diameter was generally not affected by either of the pollutants during the growing season. Although the chlorophyll content of white ash foliage was low following frequent rainfall in the early summer of 1984, there was no statistically significant evidence that acid raid or ambient ozone decreased chlorophyll in ash seedlings during the 3-year study.

The effect of simulated acid rain and ozone on the yield and quality of glasshouse-grown alfalfa

Abstract Under glasshouse conditions, alfalfa Medicago sativa L. cv ‘Saranac’ was exposed to simulated rain at pH values of 5·6 and 3·0, 1–2 times per week with or without ozone (ranging from 98 to 294 μg m −3 for 7 h/day) once a week. The pesticide diazinon (o,o-diethyl-o-(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothiate), reported as having anti-oxidant activity on pinto bean, was used in the first of these experiments, but protection from ozone injury was not observed. After weekly exposures to simulated rain and ozone over a two-month period, no yield reductions occurred in a single alfalfa harvest. When rain treatments were increased to twice weekly over two consecutive harvests, no significant yield reductions attributable to increased acidity were found. Percent dry weight in all experiments was either increased or unaffected by simulated rain and ozone exposures. Percent nitrogen, an indicator of forage quality, showed decreases of 18–37% in plants treated with simulated rain at pH 3·0 when compared with control plants. The data revealed no synergistic-like effect on both the yield and quality of alfalfa due to simulated rain and ozone.

PAN concentrations in ambient air in New jersey

The paper presented information about the occurrence of PAN in the ambient air of New Brunswick, New Jersey, during 1978-1980. The hourly PAN concentration ranged from 1 to 10.6 ppM. For 9600 readings made from September 25, 1978 to May 16, 1980. The overall average PAN concentration was 0.5 ppB. The hourly PAN concentration in New Brunswick was generally lower than that reported in many other locations. PAN concentrations in New Brunswick usually exhibited a diurnal profile similar to O/sub 3/. Stepwise multiple regressions were performed to identify factors that determined ambient air PAN concentrations at New Brunswick. 2 figures, 1 table. (DP)

Atmospheric Aldehydes Related to Petunia Leaf Damage

Snowstorm petunias grown in the greenhouse developed a necrotic banding of the actively expanding foliage characteristic of injury ascribed to various photochemically produced pollutants in the atmosphere. In this case the damage appeared to be related to the high aldehyde content of the ambient air. Each time the aldehyde concentration exceeded 0.20 parts per million for 2 hours, injury appeared within a day or two. From July to September 1963 such plant injury was observed on seven occasions.

The non-specificity of PAN symptoms on tomato foliage

Abstract The so-called classic symptoms of peroxyacetylnitrate phytotoxicity on tomato plants can result from a variety of agents including a mixture of ozone and sulphur dioxide, mites and cold temperatures. Air monitoring data are therefore essential for a positive diagnosis.

Tomato root: site of initial alteration in minor elements in cadmium treated plants

Tomato plants treated with 0.25 and 0.75 ppm Cd for one month exhibited no visual symptoms of toxicity, nor was the percent dry weight of leaf, stem, or root tissue altered. Cadmium concentrations in treated plants generally followed the trend: roots > leaves > stems. At such concentrations too low to cause phytotoxicity, cadmium altered the minor element concentration in tomato plants. The first changes occurred in the Mn and Fe concentrations of the roots. The reduction of these elements in the root may signal an early event in the mechanisms of Cd toxicity. To test the hypothesis that the root represents the primary site of injury from Cd, a kinetic study should be conducted in which root and shoot tissues are analyzed for Cd and the minor elements as the plants progress from an asymptomatic condition to one of severe Cd toxicity. (JMT)

Cadmium Contamination May Modify Response of Tomato to Atmospheric Ozone

The combined effects of cadmium contamination and ozone exposure on tomato plants were studied to determine synergistic effects. It was found that Cd and O/sub 3/ acted synergistically at certain O/sub 3/ concentrations and specific environmental conditions.

Comments on "Regional tree growth reductions due to ambient ozone: evidence from field experiments".

This paper discussed a research project which concluded that ozone adversely affected hybrid poplars by causing tree growth reductions. The author had conducted similar research using hybrid poplars and did not record growth reductions. She found that these trees were tolerant of the ambient ozone exposure.