ibclogo XVI International Botanical Congess


Abstract Number: 3112
Poster No. = 1206


GRADIENTS IN COMPATIBILITY: THE EFFECT OF FOREST FRAGMENTATION ON FRUIT PRODUCTION IN TABEBUIA ROSEA (BIGNONIACEAE)


Jennifer S. Johns and Steven N. Handel. Rutgers University, New Brunswick, NJ. USA.


We tested the hypothesis that crosses between trees within the same forest fragment are less likely to produce fruit than crosses with trees from outside the fragment in a self-incompatible tropical tree. Flowers on three focal trees were crossed with self-pollen, pollen from trees within 300 m (near), and pollen from at least 1 km away (long-distance). While pollen tubes reached the ovules in all three types of crosses, all self-pollinated flowers aborted within 48 hours. Moreover, all near crosses with trees from the same fragment also failed. Crosses with trees within 300 m but not in the same fragment, however, had a 40% success rate. Finally, long-distance crosses had a 57% success rate. We attribute this gradient in compatibility to a higher degree of relatedness among trees within the fragment.


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