Nemeth, M. Barbara , Huerta, Alfredo J. , Smith-Huerta, Nancy L. .
Effects of pollen load size and composition on pollen tube attrition, seed production, and progeny vigor in Clarkia unguiculata (Onagraceae).
Pollen load composition and size may vary both temporally and spatially in natural flower pollinations. This variation could lead to differences in the intensity of competition between pollen grains for access to ovules for fertilization. Increased competition for ovules could lead to increases in progeny vigor, if the fastest growing pollen tubes sire the most vigorous offspring. This study examines the effects of pollen load size and pollen load composition, on pollen tube attrition, seed set and seedling vigor in chamber grown plants of the wildflower Clarkia unguiculata. Pollen load composition had no effect on any of the parameters measured. Pollen load size significantly affected the number of pollen tubes in the style and number of seeds set. Pollen load size had no significant effect on attrition levels, seed weight, or any measures of seedling vigor (germination, cotyledon size, first foliar leaf size, seedling dry weight). In contrast, significant maternal effects were observed in all parameters measured with the exception of attrition levels and dry weight of seedlings. Lack of significant effects of pollen load size on progeny vigor is probably due to a combination of maternal effects and intense competition between microgametophytes in both the low and high pollen load treatments.
1 - Miami University, Department of Botany, 316 Pearson Hall, Oxford, Ohio, 45056, USA
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM