Abstract Detail

Reproductive Processes

Schlessman, Mark [1], Lee, Kevin [2], Perkins, Carrie [3], Harrington, Margaret [4].

Fruit set, mineral nutrition, and herbivory, but not mating, affect male flower production in andromonoecious Polanisia dodecandra subsp. trachysperma.

Andromonoecy, a rare sexual system in which individuals have both bisexual and male flowers, has been reported for several members of Cleomaceae; but has been largely overlooked in North American species.  In a series of controlled environment experiments, we established that the North American cleomid Polanisia dodecandra subsp. trachysperma is andromonoecious, with male flowers having aborted pistils, somewhat smaller petals than bisexual flowers, and pollen production equal to that of bisexual flowers.  Polanisia dodecandra is an annual, with flowers borne in a single large terminal raceme and typically several lateral racemes.  When we provided abundant light, water, and mineral nutrients, removed lateral raceme buds, and prevented fruit maturation by removing pistils, terminal racemes produced only bisexual flowers.  When we induced fruit production by hand-pollination, plants eventually switched to making male flowers, and thereafter continued making alternating zones of bisexual and male flowers.  Withholding mineral nutrients hastened the transition to male flowers more than inducing fruit set, and simulating leaf herbivory was equally as effective as inducing fruit set.  However, there were no differences between cross- and self-pollinated plants in the rapidity of the transition to male flower production.  The expression of andromonoecy in P. dodecandra subsp. trachysperma is very similar to that described for certain species of Cleome, for which physiological experiments indicate that male flowers are produced when a hormonal signal from developing seeds causes pistil aborton in young floral buds.  Andromonoecy has also been reported for the North American cleomids Cleome lutea, Cleomella serrulata, and Tarenaya hassleriana. We predict that future studies will show that many more North American cleomids are andromonoecious.

Related Links:
Mark Schlessman, Professor of Biology

1 - Vassar College, Biology, Box 187, Vassar College, 124 Raymond Ave., Poughkeepsie, New York, 12604, United States
2 - Dr. Bronner's, P.O. Box 1958, Vista, CA, 92085, USA
3 - University of Maryland, Plant Science and Landscape Architecture, 4291 Fieldhouse Dr., College Park, MD, 20742, USA
4 - 1117 W. Huron, Apt. 202, Ann Arbor, MI, 48103, USA


Presentation Type: Poster
Session: P, Reproductive Processes Posters
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 5:00 PM Time and date to be determined
Number: PRP007
Abstract ID:206
Candidate for Awards:None

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