Abstract Detail

Pollination Biology

SMITH-HUERTA , NANCY L [1], HUERTA, ALFREDO J [1].

Floral biology and the evolution of selfing in natural populations of Clarkia tembloriensis (Onagraceae).

Individual populations of wide-ranging plant species may vary significantly from each other with respect to certain traits which allow each population to adapt to its local environment.  One striking example of this variation is often observed as differences in floral form and breeding system.  In the California wildflower genus Clarkia, populations of outcross-pollinating individuals tend to occur near the center of the species environmental range while populations of self-pollinating individuals tend to inhabit environmentally marginal regions.   This has previously been documented in populations of Clarkia tembloriensis, the subject of this investigation.  Populations of this species fall into three types; Plants with 1) Large, strongly protandrous outcrossing flowers, 2) Small protandrous outcrossing flowers, and 3) Small non-protandrous selfing flowers.  Further variation within these three flower types includes populations of small selfing flowers that are polymorphic for a variant of petal form (crinkle petal, cp).  The aims of this study were to investigate the nature of this variation with respect to resource allocation to male and female function and to measures of floral biology important for reproductive success in the six California populations included in this study.    Results showed that more resources were allocated to pollen production relative to ovule production in large outcross-pollinating flowers than in small outcross-pollinating flowers and self-pollinating flowers.   Reproductive success was not pollen-limited in any population since more pollen was deposited on stigmas of individual flowers than the amount required to fertilize available ovules.   However not all ovules matured into seeds.  Only 25 percent of ovules from flowers in selfing populations produced seeds while 80 percent of ovules produced seeds in the out-crossing populations.  More pollen was deposited on the stigmas and more seeds were produced per capsule by cp flowers than WT flowers in the two selfing populations, although these differences were not statistically significant.   It is clear from this study that the evolution of self-pollination in certain populations of Clarkia tembloriensis has resulted in significant changes in patterns of floral resource allocation, pollen deposition, pollen tube growth and seed set in these selfing populations when compared to outcross-pollinating populations. 

1 - Miami University, Department of Biology, Oxford , OH, 45056, USA

Keywords:
Clarkia
evolution of selfing
resource allocation.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PPL001
Abstract ID:195
Candidate for Awards:None