Developmental and Structural Section
Leslie, Andrew .
Branching architecture and reproductive allocation in conifers.
Several lineages of living and extinct conifers (Cupressaceae, Podocarpaceae, fossil Araucariaceae, and fossil Cheirolepidiaceae) contain species that exhibit a growth form characterized by small, highly ramified branches bearing scale leaves. In contrast, other conifer lineages produce fewer, larger branches (Pinaceae, living Araucariaceae). These different branching habits can potentially constrain how reproductive tissue is deployed, since small branches cannot bear large reproductive cones. Quantifying pollen production in species with different branching habits is one way to explore this effect, and conifers are particularly suited to this approach because their pollen is produced in conspicuous unisexual cones. Direct counts of the number of pollen grains produced per pollen cone combined with surveys of the number of pollen cones produced per tree in several species of Cupressaceae, Taxaceae, and Pinaceae growing in southern Connecticut show that taxa with small branches produce much smaller pollen cones, but they typically produce several orders of magnitude more cone-bearing branches. This often results in roughly similar amounts of total pollen production (typically on the order of tens of billions of pollen grains) in individual trees of both small and large-branched species. These results suggest that vegetative morphology and growth form can play an important role in constraining reproductive morphology as well as determining how reproductive resources are allocated over the plant body.
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1 - Yale University, School of Forestry and Environmental Studies, 195 Prospect St., New Haven, CT, 06511, USA
pollen conepollen cone
growth habitgrowth habit.
Presentation Type: Oral Paper:Papers for Sections
Location: Portland Room/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 9:00 AM