Cardel Sharp, Yuria , Koptur, Suzanne .
Patterns of seed abortion in response to leaf herbivory in a perennial legume herb Centrosema virginianum Bentham (Fabaceae: Papilionoideae).
In many flowering plants, flowers contain more ovules than fruits have seeds. What determines which of the ovules become seeds? When resources are limited, as may happen when plants lose leaf area to herbivory, fewer fertilized ovules become seeds. Using controlled defoliation experiments and hand-pollinations in greenhouse-grown ramets of distinct individuals of a perennial herbaceous legume vine native to the southeastern U.S., we sought to answer this question. Ovules were aborted more frequently in fruits from flowers that were self-pollinated, and those on plants experiencing higher levels of defoliation. Ovules in the basal portion of the fruits were more likely to be aborted than those at the stigmatic end; and this pattern was most pronounced for fruits from self-pollination with high levels of defoliation. Competition among developing ovules in the same fruit is more intense when resources are limited by defoliation, the outcome of which may be determined by which were fertilized first. Seedling vigor was greatest for seeds developing in the middle positions of fruit produced by cross-pollination in severe herbivory treatments; no positional differences were seen for seeds from self-pollinated fruits.
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1 - Florida International University, Department of Biological Sciences, 11200 SW 8th Street, Miami, Florida, 33199, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 552B/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 2:00 PM