Pollen performance and seedling vigor in laboratory and natural populations of Clarkia unguiculata (Onagraceae)

by Ne?meth, M. Barbara.

POLLEN PERFORMANCE AND SEEDLING VIGOR IN LABORATORY AND NATURAL POPULATIONS OF CLARKIA UNGUICULATA (ONAGRACEAE) by M. Barbara Németh Effects of pollen load composition and deposition pattern on pollen performance in Clarkia unguiculata (Onagraceae). Németh, MB and NL Smith-Huerta. 2002. Int. J. Plant Sci. 163:795-802 This study explores the effect of pollen load composition and deposition patterns on pollen performance. Pollen load composition consisted of single- or two donor pollinations. Deposition patterns varied by the degree of contact among individual pollen grains. Two donor pollinations showed significantly lower germination than single donor pollinations, even without direct contact between pollen from different sources. Pollen germination decreased as contact between different types of pollen grains increased. Pollen tube attrition in the style and seed production were unaffected by pollen source or deposition scheme. Pollen deposition, pollen tube growth, seed production, and seedling performance in natural populations of Clarkia unguiculata (Onagraceae). Németh, MB and NL Smith- Huerta. 2003. Int. J. Plant Sci. 164:153-164 This study determined the potential for pollen competition in natural populations during three seasons. Pollen load sizes increased with increasing length of exposure to pollinators, varied from year to year, and from population to population. Pollen loads were large enough to result in pollen competition on the stigmas. As pollen tubes grew through the style, the opportunity for pollen competition decreased as the number of pollen tubes became smaller than the number of ovules in the ovary. Seed production was dependent on pollen load sizes, but seedling vigor was not. Effects of pollen load size and maternal plant on pollen tube attrition, seed production, and progeny vigor in Clarkia unguiculata (Onagraceae). Németh, MB and NL Smith-Huerta. 2005. Submitted. This study examines the effects of pollen load size and maternal plant on pollen tube attrition, seed set and seedling vigor in chamber grown plants. Pollen load size significantly affected the number of pollen tubes in the style and number of seeds set, but not attrition levels, seed weight, or any measures of seedling vigor. Significant maternal effects were observed in all parameters measured except attrition levels and seedling dry weight.