Ultraviolet Reflectance Characteristics in Flowers of Crucifers

Abstract

Ultraviolet reflectance properties of flowers in 26 East Mediterranean wild species and three cultivated species of the Cruciferae are surveyed. These properties were disclosed by photography of fresh or herbarium specimens through a visible‐light absorbin filter. The so‐revealed spectral polymorphism is related to the previously known visible flower colors. Ultraviolet floral patterns which act as nectar guides to pollinators are described. Hitherto unreported patterns were found to result from ultraviolet absorption by sepals, ultraviolet reflection from anther tips, and, in one case, ultraviolet absorption by a peripheral part of the corolla. In some cases patterns differ between closely related taxa and could therefore be of diagnostic value.

Phenomorphology and reproductive biology ofPinguicula longifoliaRamond ex DC. subsp.longifolia(Lentibulariaceae), a carnivorous endemic plant of the Pyrenees

“…4). This pattern is not visible to the human eye, but it is detected by many insects, and could serve as orientation guides (Horovitz and Cohen, 1972 ;Jones and Buchman, 1974 ;Silherglied, 1979 ;Kevan, 1983). The longevity of individual flowers was 27.1 ± 7.5 days (mean± standard deviation ; N = 13).…”

Genotypic variation for floral characters in Brassica and allied genera with special reference to breeding system

“…Hinata and Nishio (1980) reported that in 59 species in the Brassicinae, 50 species are self-incompatible and 9 are self-compatible. On the other hand, most previous studies that have dealt with floral diversity in members of the Cruciferae have chiefly centered on their use in taxonomic treatment and/or diagnostic descriptions of the species (Horovitz and Cohen 1972, Clemente and Hernandes-Bermejo 1980, Gómez-Campo 1980 and on intraspecific variation of floral traits for the production of F 1 hybrid seeds (Pierre et al 1999, Yoshioka et al 2005, Syafaruddin et al 2006. Little has been reported on the relationships between variations of floral characters and the breeding system.…”

Estimation of Heritability of the Nectar Guide of Flowers in Brassica rapa L.

“…It is well known that the nectar guide increases the attractiveness of flowers seen from a distance (Free 1970) and helps pollinators move toward the flower (Daumer 1958). The flowers of several cruciferous species produce nectar guides with different ultraviolet colour proportions (UVP, which represents the proportion of the flower area covered by the dark, UVabsorbing centre of the flower) that are invisible to humans, although the colour of their flowers typically appears as uniform light yellow to human eyes (Horovitz andCohen 1972, Utech andKawano 1975). Previously, we revealed wide intraspecific variations in UVP in B. rapa by UV-photography (Yoshioka et al 2005).…”