Variation in floral sex allocation in Polygonatum odoratum (Liliaceae).
OBJECTIVE
It is well known that resource allocation to male and female functions can be highly variable in hermaphroditic plants. The purpose of this study was to investigate variations in sexual investment at different levels (flower, plant and population) in Polygonatum odoratum, a plant with sequentially opening flowers.


METHODS
Pollen and ovule production in base, middle and top flowers of P. odoratum flowering shoots from two natural populations were quantified. Plant measurements of phenotypic and functional gender were calculated in both populations. Total leaf number was used to investigate the relationship between gender assessments and plant size.


RESULTS
Pollen and ovule production varied depending on flower position, although the precise pattern differed between both studied populations; only investment in female floral function decreased markedly from base to top flowers in both populations. The frequency distribution of phenotypic gender and their relationship with plant size differed between populations. Phenotypic and functional gender were correlated in both populations.


CONCLUSIONS
Sexual investment in P. odoratum has shown a marked variability within plants, among plants, and between populations, which confirms the importance of analysing sex expression in plants of this type. Differences in relative investment in male and female components (phenotypic gender) are reflected in the functional gender and it would be expected that the evolution of sexual specialization in Polygonatum odoratum would be promoted.
Departamento de Botánica, Universidad de Santiago de Compostela, Campus Sur, 15782 Santiago, Spain. bvjguiti@usc.es
Javier
J
Guitián
Mónica
M
Medrano
José E
JE
Oti
D000704:Analysis of Variance; D035264:Flowers / Q000033:anatomy & histology / Q000502:physiology*; D014644:Genetic Variation; D010641:Phenotype; D031384:Polygonatum / Q000235:genetics / Q000502:physiology*; D012727:Sex Characteristics; D012744:Sex Ratio