Ecological and physiological implications of a vernalization requirement for flowering in creeping herbaceous perennial plants

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Creeping herbaceous perennial plants commonly occur as weeds in agricultural and natural ecosystems in Canada, with many species causing significant economic losses in agriculture and environmental damage in natural ecosystems. Reproducing by seeds and vegetative reproductive structures, these plants have complex life histories and must maintain a balance between flowering and non-flowering meristems to sustain the perennial growth habit. This balance is maintained through the production of dormant or non-dormant buds on vegetative reproductive structures, or through the production of vegetative and flowering shoots, or ramets. Mechanisms regulating ramet development vary, but vernalization (cold exposure) is thought to play a role in some species and has been confirmed in the creeping herbaceous perennial plant red sorrel. Successful management of these plants requires extensive knowledge of the mechanisms regulating plant reproductive biology, and the physiological, ecological, and management implications of vernalization in perennial weeds has not been explored. Red sorrel commonly occurs as a weed in many plant communities in Atlantic Canada, making it a good model species for studying the implications of vernalization in creeping herbaceous perennial weeds. The overall goal of this research is to increase our understanding of the reproductive biology of creeping herbaceous perennial plants, with particular emphasis on the role of vernalization in regulating plant growth and development. In the short term (1 to 5 years), I will use greenhouse and field experiments to determine i) the effects of juvenility and seed and root bud vernalization on flowering, ii) the effect of ramet emergence timing on vernalization response and flowering, iii) the timing of flower primordia formation in vernalized ramets, and iv) if ramets flower repeatedly prior to senescence. Over the long term (5 to 10 years), I want to determine i) if the flower stimulus can be transferred between interconnected ramets, ii) the nature of genetic changes associated with vernalization in creeping herbaceous perennial plants, and iii) the effects of a ramet vernalization requirement on whole-plant growth and development. This research will contribute new knowledge on the role of vernalization in regulating ramet development, whole-plant growth, and population maintenance of creeping herbaceous perennial plants. Additional benefits, however, will arise from the research as our model species is an economically important weed. As such, my research will contribute knowledge that will improve perennial weed management in natural and agricultural plant communities in Northeastern North America. The rationale for this research is that vernalization has unique implications for plant growth and development in creeping herbaceous perennial plants, and that red sorrel is a good model plant species to study this.