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The Chemistry and Physiology of Pigmentation in Leaves Injured by Air Pollution
Author(s) -
Howell R. K.,
Kremer D. F.
Publication year - 1973
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1973.00472425000200040004x
Subject(s) - pigment , chemistry , ozone , biological pigment , pollutant , phaseolus , phenols , botany , amino acid , phenol , environmental chemistry , organic chemistry , food science , biochemistry , biology
Oxidant air pollutants induce necrotic lesions and discoloration on foliage of susceptible plants. The time of initiation of oxidized plant pigments in response to ozone and the chemical composition of the pigments were investigated. Plants of Phaseolus vulgaris humilis L., with nearly fully expanded leaves, were treated with ozone. Leaves removed immediately, 2, 4, and 24 hours after treatment were examined for presence of induced pigment. Milligram quantities of polymerized pigments were extracted from treated leaves, freed from extraneous materials by Sephadex and molecular sieves, and analyzed for chemical constituents. Pigments are initiated within 2 hours after exposure and have a molecular weight range of 10,000 to 26,000. Twenty amino acids, seven metals, two sugars, and one phenol moiety were identified from the polymers. Pigment formation associated with ozone injury appears to result from ozone injury to membranes which permits phenols and phenolases to react and to produce quinones which polymerize with amino acids and proteins. Thus, this oxidative process enhanced by air pollutants may reduce nutritional values in leafy food and forage crops.