Document Detail

Image analysis of epicuticular damage to foliage caused by dry deposition of the air pollutant nitric acid.
MedLine Citation:
PMID:  19137141     Owner:  NLM     Status:  MEDLINE    
Nitric acid vapor is produced by the same photochemical processes that produce ozone. In the laboratory, concentrated nitric acid is a strong acid and a powerful oxidant. In the environment, where the concentrations are much lower, it is an innocuous source of plant nitrogen. As an air pollutant, which mode of action does dry deposition of nitric acid follow? We investigated the effects of dry deposition of nitric acid on the foliage of four tree species native to the western United States. A novel controlled environment, fumigation system enabled a four-week exposure at concentrations consistent with ambient diurnal patterns. Scanning electron microscopy and automated image analysis revealed changes in the epicuticular wax layer during fumigation. Exposure to nitric acid resulted in a reproducible suite of damage symptoms that increased with increasing dose. Each tree species tested exhibited a unique set of damage features, including cracks, lesions, and conformation changes to epicuticular crystallite structures. Dry deposition of atmospheric nitric acid caused substantial perturbation to the epicuticular surface of all four tree species investigated, consistent with the chemical oxidation of epicuticular waxes. Automated image analysis eliminated many biases that can trouble microscopy studies. Trade names and commercial enterprises or products are mentioned solely for information. No endorsements by the U.S. Department of Agriculture are implied.
Pamela E Padgett; Sally D Parry; Andrzej Bytnerowicz; Robert L Heath
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2008-10-23
Journal Detail:
Title:  Journal of environmental monitoring : JEM     Volume:  11     ISSN:  1464-0333     ISO Abbreviation:  J Environ Monit     Publication Date:  2009 Jan 
Date Detail:
Created Date:  2009-01-12     Completed Date:  2009-02-25     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100968688     Medline TA:  J Environ Monit     Country:  England    
Other Details:
Languages:  eng     Pagination:  63-74     Citation Subset:  IM    
Riverside Fire Laboratory, USDA Forest Service, Riverside, CA 92507.
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MeSH Terms
Abies / drug effects,  ultrastructure
Air Pollutants / pharmacology*
Environment, Controlled
Image Processing, Computer-Assisted
Microscopy, Electron, Scanning
Nitric Acid / pharmacology*
Pinus / drug effects,  ultrastructure
Plant Leaves / drug effects*,  ultrastructure
Quercus / drug effects,  ultrastructure
Reg. No./Substance:
0/Air Pollutants; 7697-37-2/Nitric Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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