Clonal variation: birth order produces life-history diversity in the Greater Duckweed, Spirodela polyrhiza

It appears your Web browser is not configured to display PDF files. Download adobe Acrobat or click here to download the PDF file.

Click here to download the PDF file.


Mejbel, Hebah




Evolutionary response to environmental variation is required for survival and may occur through adaptive tracking, phenotypic plasticity or bet hedging. Variable dormancy is a classical bet-hedging trait in literature, and enables survival through harsh conditions. Greater Duckweed, Spirodela polyrhiza, forms overwintering propagules called “turions”. However, S. polyrhiza propagates clonally, and it is unknown how diversified dormancy behaviour is generated among genetically identical offspring. Here, I investigate sources of variation in turion formation in Spirodela polyrhiza. I tested whether turion production is stimulated by birth order, size and temperature under controlled conditions of a growth chamber and a thermogradient incubator. Parental birth order was found to have a significant effect on turion formation; furthermore, this effect is temperature-dependent. This study addresses fundamental questions on mechanisms generating diversity in dormancy behavior, and provides insight into the natural history of Spirodela polyrhiza, an emerging model organism for ecological studies.






Carleton University

Thesis Degree Name: 

Master of Science: 

Thesis Degree Level: 


Thesis Degree Discipline: 


Parent Collection: 

Theses and Dissertations

Items in CURVE are protected by copyright, with all rights reserved, unless otherwise indicated. They are made available with permission from the author(s).