Variation in pollen limitation among plants and phenotypic selectionon floral traits in an early-spring flowering herb

Autor: Vie, Erik U., Dahl, Vibeke, Pedersen, Tom R., Houge, Siri, Eide, Wenche, Andersen, Heidi L., Totland, Orjan, Bjelland, Torbjorg
Předmět:
Zdroj: Oikos; Sep1998, Vol. 82 Issue 3, p491-501, 11p
Abstrakt: Female reproductive success in animal pollinated plants may be limited by the amount of suitable pollen that reaches stigmas, but little knowledge exists on how the extent of pollen limitation varies among plants of the same population. Here we ask; (1) if there is pollen limitation at the whole population level in a Norwegian population of an early spring blooming herb, Crocus vernus, (2) if so, if a variation in pollen limitation exists among plants, (3) over which plant traits this variation occurs, and (4) if there is phenotypic selection onplant traits caused by pollen limitation. Pollen limitation on seed number and seed:ovule ratio occurred at the whole population level. By measuring flowering time, plant size, and various aspects of floraldisplay on both supplementary hand-pollinated plants and control plants, we found a significant relationship between reproductive successand petal size in the control plants, but not in plants that received additional pollen. Reproductive success of plants with white stigmas were more pollen limited than that in orange-stigma plants. It is likely that plants with small petals and white stigmas have lower chances of being recognized by pollinators (Apis mellifera), and that this causes the pollen limitation on reproductive success in such plants. Multivariate selection analyses showed significant linear selectionon petal size in control plants, but not in extra-pollinated plants,suggesting pollinator mediated selection on petal size. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index