LB 14-170 - Effect of pollen-donor distance and prey capture on reproductive success in a carnivorous plant

Background/Question/Methods:

The maintenance of genetic diversity has important consequences for plant populations. Because plants are sessile, the distance between plants is often inversely correlated with relatedness. Therefore, the distance between pollen-donor and recipient can determine the level of inbreeding or outbreeding. Furthermore, nutrient availability can interact in complex ways with the level of inbreeding to affect reproductive success in populations of flowering plants.

Populations of the carnivorous plant Sarracenia alata have decreased in size and become extremely fragmented due to habitat loss and land-use changes. The purpose of this study was to examine the effects of pollen-donor distance, prey capture, and their interaction on reproductive success in S. alata. We hand-pollinated flowers with pollen from varying distances [0 m (self-pollinated) and 35, 60, 90, 125, and 190 m], and we prevented prey capture in half of our study plants. We measured seed production and germination as estimates of reproductive success.

Results/Conclusions:

There was a positive relationship between pollen-donor distance and the number of seeds produced, but pollen-donor distance did not affect germinability. There was no effect of either prey capture alone or the interaction between pollen-donor distance and prey capture on either seed production or germination rate. These results show that, within the range of pollen transfers made, reproductive success increases with distance between pollen donor and recipient. Current-season prey capture had no significant effect on reproductive success, suggesting that all nutrients for reproduction were mobilized from storage. More research is needed to understand source-sink relationships among prey capture, storage, production of new tissues, and reproduction in S. alata.