Relative contributions of sexual and asexual reproduction in Lysimachia terrestris
LE3 .A278 2017
Bachelor of Science
Lysimachia terrestris (Myrsinaceae) is one of few species within the genus Lysimachia known to asexually reproduce via bulbil formation. It is unknown if pollination and subsequent fruit and seed production inhibits or reduces bulbil formation in L. terrestris. To examine whether there is a tradeoff between asexual and sexual modes of reproduction in this species, populations were investigated in Middleton and Wolfville, Nova Scotia. Impact upon bulbil production was monitored through application of pollinator exclusion bags prior to anthesis to modify pollination and fruit set. Treatments comprised zero, two, six, twelve, or all flowers, being left open to pollinators to determine if a threshold number of pollinated flowers alters the number of bulbils formed. Counts of the number of bulbils, flowers, fruits, seeds and infertilized ovules were analyzed among treated plants. Using light and scanning electron microscopy techniques, fruit and bulbil development were also examined. Results suggest that bulbil formation is limited, but not restricted by seed production. Additionally, investment in sexual reproduction was observed to be larger at the Middleton location. There is anecdotal evidence of the presence of a specialist pollinator, Macropis nuda (Hymenoptera: Mellitidae), but none were observed. These findings provide new insight into the conditions influencing bulbil yield in L. terrestris and the ecological roles of both asexual and sexual reproduction.
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