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DIFFERENTIAL RESPONSES OF PLANT FOLIAGE TO SIMULATED ACID RAIN
Author(s) -
Evans Lance S.,
Curry Thérèse M.
Publication year - 1979
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1979.tb06306.x
Subject(s) - pteridium aquilinum , biology , tradescantia , acid rain , frond , botany , horticulture , fern , commelinaceae , ecology
Experiments were performed to show the responses of foliage of several clones of Tradescantia sp., Pteridium aquilinum, Quercus palustris , and Glycine max to simulated acid rain. These experiments were performed to (a) predict the relative sensitivities of foliage of these plants to acid rain, and (b) identify leaf surface and anatomical alterations to simulated acid rain that may be used to diagnose acid rain injury. Plants were exposed to simulated rain at pH levels of 5.7, 3.4, 3.1, 2.9, 2.7, 2.5, and 2.3. Sporophyte leaves of bracken fern {P. aquilinum) were most sensitive to simulated acid rain among the species tested. About 10% of the surface area of older leaves of P. aquilinum was injured after exposure to 10 rainfalls at pH 2.5 (a single 20‐min rainfall daily). Foliage of pin oak ( Q. palustris) exhibited less than one‐percent leaf area injury after exposure to simulated rain at pH 2.5 after 10 rainfalls (one 20‐min rainfall daily). The responses of soybeans ( G. max ) and spiderwort (Tradescantia sp.) were intermediate between these two extremes. Histological observations show that lesion development results in collapsed leaf tissue in all four species. Gall formation that resulted from both cell hypertrophy and hyperplasia occurred in lesions of Tradescantia , and Q. palustris . Limited hyperplastic and hypertrophic reactions occurred in G. max foliage after exposure to simulated acid rain but no leaf galls resulted. Sporophyte foliage of P. aquilinum exhibited a “granular” type abnormality in the cytoplasm prior to the collapse of some epidermal cells injured by simulated rain. Injury occurred most frequently near vascular tissues and trichomes in all four species. In general, plant species that show cell hyperplasia and hypertrophy of leaf tissues after exposure to simulated acid rain are injured less than species that do not show these responses.