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RELATIONSHIP BETWEEN DOSE OF SO 2 AND NO 2 MIXTURES AND GROWTH OF POA PRATENSIS
Author(s) -
WHITMORE MARY E.
Publication year - 1985
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1985.tb03682.x
Subject(s) - poa pratensis , chemistry , zoology , horticulture , toxicology , botany , biology , poaceae
S ummary A series of experiments was conducted in controlled environment chambers to investigate the relationship between the concentration of mixtures of SO 2 and NO 2 , length of exposure and growth of the amenity grass Poa pratensis L. cv. Monopoly. Plants were exposed to concentrations of 40, 70 and 100 nl 1 −1 SO 2 and NO 2 , in one to one ratio, for periods of 20, 34 and 38 d and compared with controls grown in partially filtered air. The effects of the pollutants on plant dry weight were related to the product of exposure concentration and duration within the limits of the experimental conditions. A dose‐response curve was therefore constructed which illustrated that although small doses may have no effect or may even stimulate growth, slightly larger doses may be severely inhibitory. In order to clarify the effects of small doses a further experiment was performed in which the response was observed at intervals during a 50 d exposure to 40 nl 1 −1 SO 2 plus 40 nl 1 −1 NO 2 . The results confirmed that low doses could cause small growth stimulations and that the transition from beneficial to inhibitory effects occurs over a narrow range of doses. A subsequent exploratory experiment provided an example of how the environmental conditions during exposure may affect this relationship, and illustrated that each dose‐response curve is only applicable to a given set of conditions.