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Photosynthetic and stomatal conductance responses to acid mist of red spruce seedlings
Author(s) -
EAMUS D.,
FOWLER D.
Publication year - 1990
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1990.tb02138.x
Subject(s) - photosynthesis , stomatal conductance , mist , chemistry , chlorophyll , carbon dioxide , horticulture , botany , chlorophyll a , biology , physics , organic chemistry , meteorology
Two‐year‐old seedlings of Picea rubens , growing in open‐top chambers in Scotland were treated twice weekly from July 1987 to December 1987, with mist containing ammonium sulphate and nitric acid at a pH of either 2.5 or 5.0. The response of photosynthesis and stomatal conductance to light flux density and carbon dioxide concentration were measured in March 1989. Leaf chlorophyll a and b contents were also measured. Acid mist (pH 2.5) resulted in several significant changes. First, both the rate of light saturated photosynthesis (A max ) and CO 2 ‐ saturated rate of photosynthesis (J) were substantially increased, when expressed per unit leaf area. Second, the apparent quantum yield and chlorophylls a and b content increased. Third, as a consequence of the greater chlorophyll content of the leaves treated with acid mist, the rate of A max , and J, expressed per unit chlorophyll, was substantially reduced in pH 2.5 treated branches. Stomatal conductance was enhanced at all but the highest light flux densities, and was independent of the CO 2 concentration, remaining high for all values of CO 2 concentration used. These results show that acid mist caused a number of responses in the gas exchange and photosynthetic properties of red spruce.