Variation in nectar production across inflorescence positions in Gladiolus grandiflorus cultivars

Gladiolus, a genus within the Iridaceae family, is native to Africa. Floret development and reproductive success in Gladiolus species exhibit temporal and spatial variation within inflorescences. Spatiotemporal variation in nectar distribution influences pollinator foraging among florets and plants. This study investigated intra-inflorescence variation in reproductive traits of three Gladiolus grandiflorus cultivars. Floret opening progressed acropetally within the inflorescence. Floret anthesis lasted two to four days. Pollen viability was observed between 11:00 and 17:00 across all three inflorescence positions. Nectar production varied significantly among florets within the inflorescence. Florets in the second position of the inflorescence exhibited the highest nectar volume across all evaluated cultivars. Fruit set and seed development declined significantly from basal to distal positions. No fruit set occurred in the spontaneous self-pollination treatment. The findings suggest that high variability in nectar production among plants in the same environment may mask the reproductive disadvantage of individuals with low or no nectar production.