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dc.contributor.supervisor Rood, Stewart B.
dc.contributor.author Nielsen, Julie L.
dc.contributor.author University of Lethbridge. Faculty of Arts and Science
dc.date.accessioned 2011-06-14T21:29:42Z
dc.date.available 2011-06-14T21:29:42Z
dc.date.issued 2009
dc.identifier.uri https://hdl.handle.net/10133/1291
dc.description xiii, 117 leaves : ill. ; 29 cm en_US
dc.description.abstract Cottonwoods are poplar trees that are adapted to riparian zones that are naturally occasionally flooded. Like all Salicaceae, cottonwoods are dioecious and prior studies have indicated that males are more drought-tolerant than females and found more often in poorer, drier sites. We investigated sex differentiation of cottonwoods in response to the opposite water-stress, flood, and predicted that the increased water-stress tolerance of males in drought would also apply to flood-stress. Twenty-one clones of male and female narrowleaf cottonwoods (Populus angustifolia) were grown in a greenhouse along with three female clones of the hybrid native lanceleaf cottonwood (P. x acuminata) for comparison. It was anticipated that the hybrids would show the fastest growth owing to the genetic contribution from the P. deltoides parent and its rapid intrinsic growth rate. Flood reduced heights and the numbers and sizes of leaves and roots, and consequently dry weights, abaxial stomatal conductance and leaf chlorophyll. Inundation increased carbon:nitrogen, but did not alter stomatal density, leaf water potential, or δ13C. The hybrid saplings were much larger than the narrowleaf saplings but their proportional growth reduction with flooding was greater than in the female P. angustifolia, suggesting higher flood-tolerance of the narrowleaf cottonwood. P. angustifolia sexes performed similarly under reference conditions but the males were proportionally more inhibited by flood, suggesting sex differentiation in flood-tolerance. This study indicates that riparian cottonwoods are reasonably flood-tolerant but slight differences exist between the sexes and to a greater extent, across taxa. While prior studies have indicated males are apparently more tolerant of drought, females are probably more flood-tolerant. en_US
dc.language.iso en_US en_US
dc.publisher Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2009 en_US
dc.relation.ispartofseries Thesis (University of Lethbridge. Faculty of Arts and Science) en_US
dc.subject Cottonwood -- Effect of floods on en_US
dc.subject Dissertations, Academic en_US
dc.title The responses of female and male cottonwood saplings to flooding en_US
dc.type Thesis en_US
dc.publisher.faculty Arts and Science en_US
dc.publisher.department Department of Biological Sciences en_US
dc.degree.level Masters


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