Exploring the limiting causes of fruit production in the tropical tree Ipomoea wolcottiana Rose (Convolvulaceae)
2003
Parra-Tabla, V. | Bullock, S.H.
Path analysis was used to evaluate a group of variables related to fruit production in the tropical tree Ipomoea wolcottiana (Convolvulaceae). The variables were tree size (trunk diameter), available phosphorus in the soil, floral phenotypic sex expression (i.e. gynoecium biomass allocation), flower production, fruits initiated, and length of the corolla and diameter of its opening. The path model explained 79.9% of the total variation, and the production of mature fruits was related in large part by the number of fruits initiated and by phenotypic sex expression. In turn, fruits initiated were related to corolla tube diameter and to a lesser extent to corolla tube length. The model could explain a low percentage of the variation (18.5%) of the number of fruits initiated, but once a fruit was initiated it had a high probability of maturing. Phenotypic sex expression related negatively to the number of flowers produced and positively, to almost the same degree, to available phosphorus in the soil. Tree size had a positive effect on flower production but a negligible effect on fruits initiated and matured. Soil phosphorus affected positively, although weakly all variables. The relationships between tree size, number of flowers and phenotypic sex expression suggested that abundant flowering in this species functions more for pollen donation than its reception.
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