Document: ANN-3-21-8

Life-history trade-offs, preformation, and dynamic resource allocation by a carnivorous herb, Pinguicula vulgaris (Lentibulariaceae).

WORLEY, A.C.*

Department of Botany, University of Toronto, Toronto, ON, Canada ¹

Abstract:
Investment by perennial plants in reproduction and vegetative functions often reflects two size-dependent features: current versus future reproductive potential, and the likelihood of surviving to reproduce again. However, increased allocation to a particular function may also reflect its capacity to accommodate increased resources, rather than strategic emphasis. I investigated resource allocation to reproduction, growth and vegetative propagation by Pinguicula vulgaris. Allocation to growth varied negatively with plant size, particularly in large fruiting plants, whereas sexual reproduction and gemmae production varied positively with plant size. These allocation patterns suggested an emphasis on growth until a minimum size was reached. Beyond this threshold, resources not required to maintain size appeared to be allocated to current reproduction. In response to one season of resource supplementation (feeding with fruit flies), fed plants attained a mass 60 % greater than control plants, and produced more gemmae. However, feeding did not alter the within-season incidence of either flowering or fruiting, even in large plants that might be expected to increase reproductive allocation. This lack of immediate response occurred because floral primordia differentiated up to 10 months before the growing season. However, enhanced resource status likely affected future reproduction indirectly through resource effects on plant size. These results illustrate that preformation can delay responses to enhanced resources by perennial plants. Comparisons among Pinguicula species with and without preformation should further clarify its ecological consequences.

Keywords: growth, fruit production, plant size, trade-offs, vegetative propagation

This abstract is being presented at: 8:55 AM in session:
Symposium # 19: Carnivorous Plants as Model Ecological Systems.