Étude de certains facteurs influençant la production de fruits et de ramets floraux chez la chicouté (Rubus chamaemorus)

Authors: Gauci, Rachel
Advisor: Lapointe, Line
Abstract: Competition for both carbon and mineral resources between the different sinks has often been reported in perennial plants and can, especially in presence of asexual reproduction, reduces the production of fruits. We have studied carbon and nutrient allocation in cloudberry (Rubus chamaemorus L., Rosaceae), a northern clonal plant, to determine the limiting factors for both flower ramets and fruit production. Furthermore, the plant producing more ramets when its rhizomes grow near the ground surface than deeper in the soil, the impact of some edaphic factors (temperature and soil pressure) on the rhizome apex differentiation into buds was thus also quantified along with the impact of apical dominance and of the level of carbon and nutrient reserves Our results indicated that carbon is more limiting than nutrients for fruit production and that this carbon comes essentially from the floral shoot. During early spring, the carbon reserves are low in the rhizome most likely due to a weak dormancy of the rhizome during the winter. The developing fruits and the unfolding leaves appear to compete for the carbon resource. Additionally, the shoots bearing an aborting fruit had a low P content in their leaves, a deficiency that can reduce carbon translocation to the fruits. Moreover, aborted cloudberry fruits have a low K concentration, which could also limit sugar import to these fruits and induce abortion. However, mineral fertilization did not improve fruit yield, at least on a short-time scale. Longer-term studies of mineral fertilization coupled with the selection of clones with faster leaf unfolding and with a deeper dormancy of the rhizome could increase cloudberry fruit yield. Two factors contributed to increase flower bud production: mineral fertilization and high temperatures. However, none of these factors appeared to work as a triggering factor for floral bud formation. Other studies will be necessary to identify the factors inducing rhizome apex differentiation into leaf and flower buds in cloudberry.
Document Type: Thèse de doctorat
Issue Date: 2008
Open Access Date: 13 April 2018
Permalink: http://hdl.handle.net/20.500.11794/20553
Grantor: Université Laval
Collection:Thèses et mémoires

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