Symbioses: Plant, Animal, and Microbe Interactions
Taylor, Jeff H. , Dobson, Sarah , Mullendore, Sara , Bintrim, Tyler , Collin, Carine L. , Ashman, Tia-Lynn .
Impacts of Fragaria virginiana reproduction on the fungal density in a mycorrhizal association.
Fragaria virginiana, the wild strawberry plant, is interesting in its reproduction in that it is gynodioecious. Individual plants are either female or hermaphrodites. The proposed metabolic impact of this on the plants is very interesting. During flowering, the hermaphrodite must support the structures of both sexes, seemingly stressing it more than its exclusively female counterpart. Conversely, the female typically experiences greater fruit set, increasing its metabolic demand during that phase. Unfortunately, detecting the impacts of these predicted differences in metabolic demand has been difficult. In the current study, the metabolic impact of reproduction in F. virginiana was assessed using mycorrhizal density. Both field-and greenhouse-grown F. virginiana plants were analyzed over their reproductive phase. To assess mycorrhizal density, root samples were cleared, and then stained with Trypan blue to reveal fungal structures. The number of vesicles, which are the most discernable feature of the vesicular-arbusuclar morphotype commonly found associated with F. virginiana, were scored per unit root length. Results for the field grown plants were largely obscured by the very high levels of variability with regard to the number of vesicles present. It was unclear if this is a product of the varying microenvironments experienced by regions of the root system, or due some anatomical difference among the fungal species present. The greenhouse-grown plants had much lower variability, and it was noted that the vesicle density dropped significantly in the hermaphroditic plants post-flowering. Interestingly, this correlated with a significantly higher photosynthetic rate of the hermaphroditic plants during flowing. From these results, we conclude that the increased flowering stress of the hermaphrodites during flowering does induce a delayed impact on vesicle density. However, the difference is so slight as to only be observable under the reduced variability environment of the greenhouse.
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1 - Slippery Rock University of Pennsylvania, Department of Biology, Slippery Rock, PA, 16057, U.S.A.
2 - University of Pittsburgh, Department of Biological Sciences, Pittsburgh, PA, 15260, U.S.A.
3 - University of Pittsburgh, Department of Biological Sciences, Langley Hall, Pittsburgh, Pennsylvania, 15260, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Continental B/Hilton
Date: Wednesday, July 11th, 2007
Time: 1:15 PM