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Application of a Thermal Gradient Bar to the Study of Germination Patterns in Successional Herbs
Richard H. Wagner
The American Midland Naturalist
Vol. 77, No. 1 (Jan., 1967), pp. 86-92
Published by: The University of Notre Dame
Stable URL: http://www.jstor.org/stable/2423428
Page Count: 7
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A thermal gradient bar was used to investigate the germination temperature optima (GTO) for various successional herbs. Four species of Plantago were investigated: P. major and P. rugelii had a GTO of about 28 C, whereas P. arisrata and P. virginica showed a GTO of about 16 C. These optima were correlated with germination patterns in the field. The first pair normally germinates in early summer at relatively high mean surface soil temperatures; the second pair germinates in fall at low mean surface soil temperatures. The thermal gradient bar appears to be a useful tool in dealing with these relations of phenology and physiology.
The American Midland Naturalist © 1967 The University of Notre Dame