Effect of pollen competition on offspring quality at varying stages of the life cycle in Silene latifolia Poiret (Caryophyllaceae)

Abstract

from the ovary. We performed an experiment in which we placed excess pollen at one of two distances from the ovary. We then compared seed, seedling, and adult characters of the progeny resulting from these two treatments. Pollen placement had a statistically significant effect on adult sex ratio, with progeny resulting from more intense pollen competition containing a statistical excess of males, and progeny resulting from less intense competition containing a nonsignificant excess of females. Pollen placement did not have a statistically significant effect on any of seven measures of offspring quality (seed number per fruit, mean seed mass, seedling emergence time, cotyledon area after two weeks, leaf area after four weeks, above-ground dry weight after six weeks, and days required to flower). Since one of our dependent variables (seedling emergence time) was found to be significantly affected by pollen competition in an earlier study, it appears that such traits may be as much influenced by parental, environmental, or population-level effects as by pollen competition.