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Rapid Population Differentiation in a Mosaic Environment. I. The Response of Anthoxanthum odoratum Populations to Soils
R. W. Snaydon
Vol. 24, No. 2 (Jun., 1970), pp. 257-269
Published by: Society for the Study of Evolution
Stable URL: http://www.jstor.org/stable/2406802
Page Count: 13
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1) Populations of the grass Anthoxanthum odoratum were collected from the mosaic of contrasting soil environments of the Park Grass Experiment, Rothamsted, where plots (35 m x 20 m) have received different liming treatments for 40-60 years. 2) The populations were grown on calcareous and acid soils. Populations from limed plots (pH 7) grow more rapidly on calcareous soil, but those from unlimed plots (pH 4) grew more rapidly on acid soil; the response of populations to these soils was correlated (r = 0.95) with the soil pH of their source plots. 3) Population samples grown from seed collections were very similar to those grown from tiller collections; it is concluded that the populations have reached genetic equilibrium with the contrasting and recently created soil environments, and that there was little gene flow between contiguous plots. 4) The differences between Park Grass populations, in response to contrasting soils, were significantly less than the differences between comparable natural populations; this may be the result of limited genetic variability within the original Park Grass population. 5) Park Grass populations were genetically less variable than natural populations in their response to soil, but were genetically more variable than natural populations in four other morphological characters. 6) The phenotypic stability of Park Grass populations was greater than that of natural populations. 7) There has apparently been evolution of specific adaptation, and possibly of increased adaptability, among populations in less than 40 years and over distances of less than 30 m within this mosaic environment.
Evolution © 1970 Society for the Study of Evolution