Cl. Jolls et al., SPECTROPHOTOMETRIC ANALYSIS OF NECTAR PRODUCTION IN SILENE VULGARIS (CARYOPHYLLACEAE), American journal of botany, 81(1), 1994, pp. 60-64
Significant differences in nectar content were observed between hermap
hrodite and female plants of the gynomonoecious-gynodioecious taxon, S
ilene vulgaris, from populations in northern lower Michigan. These dif
ferences in nectar sugar content were observable with a carbohydrate d
igestion technique involving sulfuric acid, phenol, and measurement of
the color change with a spectrophotometer. A hand-held refractometer
did not provide sufficient resolution to discern differences between t
he genders. Both genders were similar in the pattern of sugar content
of nectar during floral development. A split-plot factorial design rev
ealed significant differences both among individual plants and stages
of floral phenology within each gender. The spectrophotometric techniq
ue and statistical analysis provided the needed resolution to discern
differences between the genders that we relate to pollinator activity,
levels of inbreeding depression, and the maintenance of gynodioecy in
this taxon.