Abstract

Pollen competitive ability depends on the innate capacity of a pollen donor to produce pollen that reaches the ovules fast, but could also be a consequence of the ability to interfere with pollen from other donors. In a greenhouse study on Viola tricolor, we examined the relative importance of both of these effects by performing crosses where we varied the pollen load composition of two donors. We found that when a pollen donor had higher in vitro pollen tube growth rate than a competitor, this donor sired proportionally more seeds in most cases. At very low proportions, however, there was no benefit of producing fast growing pollen. We further investigated the potential for pollen interactions by comparing in vitro performance in single- and mixed-donor batches of the same density. Pollen tube growth rate differed between treatments in some donor combinations, indicating that pollen from different donors interact. Only donors with the faster growing pollen tubes in the single samples showed signs of interference in the mixtures. Donors with slower pollen tube growth had an increased growth rate when mixed. Although our results suggest interactions between pollen grains from different donors that might affect siring ability, the intrinsic pollen tube growth rate was more important for siring ability in this species.

Keywords

pollen competition; pollen interactions; pollen tube growth rate; sexual selection in plants; Viola tricolor

Published in

Evolutionary Ecology Research
2002, Volume: 4, number: 5, pages: 687-700
Publisher: EVOLUTIONARY ECOLOGY LTD

UKÄ Subject classification

Ecology
Evolutionary Biology


Permanent link to this page (URI)

https://res.slu.se/id/publ/42097