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Reduced Seed Germination after Pappus Removal in the North American Dandelion (Taraxacum officinale; Asteraceae)

Published online by Cambridge University Press:  20 January 2017

Alison N. Hale ,
Samantha M. Imfeld ,
Chloé E. Hart ,
Kevin M. Gribbins ,
Jay A. Yoder  and
Matthew H. Collier
Alison N. Hale
Affiliation:
Department of Biology, Wittenberg University, Springfield, OH 45501-0720
Samantha M. Imfeld
Affiliation:
Department of Biology, Wittenberg University, Springfield, OH 45501-0720
Chloé E. Hart
Affiliation:
Department of Biology, Wittenberg University, Springfield, OH 45501-0720
Kevin M. Gribbins
Affiliation:
Department of Biology, Wittenberg University, Springfield, OH 45501-0720
Jay A. Yoder
Affiliation:
Department of Biology, Wittenberg University, Springfield, OH 45501-0720
Matthew H. Collier*
Affiliation:
Department of Biology, Wittenberg University, Springfield, OH 45501-0720
*
Corresponding author's E-mail: [email protected]
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Abstract

This study examined seed ultrastructure in relation to germination of North American dandelion seeds. Based on laboratory rearing observations, it was thought that the design of the pappus acts as a conduit facilitating water entry into the seed. It was hypothesized that seeds without a pappus would yield fewer seedlings and require more time to germinate than seeds with an intact pappus. Seed ultrastructure was investigated using scanning electron microscopy, while relative humidity and fungal association were explored as factors that may confer an advantage to intact seeds. Results indicate that germination for seeds lacking a pappus is 31% lower than control seeds (with an intact pappus) and that the seeds lacking a pappus require more time to germinate. Relative humidity did not differentially affect germination, and while a fungus Cladosporium cladosporioides was recovered internally, its presence neither enhanced germination nor decreased time to germination when tested by antimycotic removal. Electron micrographs revealed that (1) the pappus is hollow and (2) the pericarp of the fruit fuses with and partially encloses the pappus. Fusion of the pappus with the fruit suggests that this structure acts as a device to regulate seed hydration.

Keywords

North American dandelion, Taraxacum officinale G. H. Weber ex WiggersCladosporium cladosporioidesSeed ultrastructurescanning electron microscopyachene
Type
Weed Biology and Ecology
Information
Weed Science , Volume 58 , Issue 4 , December 2010 , pp. 420 - 425
Copyright
Copyright © Weed Science Society of America 

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