Tagged: zygomorphy

Zygomorphy evolved from disymmetry in Fumarioideae

Zygomorphy evolved from disymmetry in Fumarioideae

Floral bilateral symmetry (zygomorphy) has evolved at least 70 times during the history of angiosperms, whilst radial symmetry (actinomorphy) is the ancestral and most common state for angiosperms as a whole. Sauquet et al. reconstruct the phylogeny and floral evolution of Papaveraceae (Ranunculales) and find that in this family zygomorphy evolved from a rare, intermediate symmetry form, disymmetry, which is defined by two perpendicular planes of bilateral symmetry. This important transition occurred in subfamily Fumarioideae (fumitories) and is correlated with the loss of a nectar spur.

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Pollination, flower size variation and floral symmetry

Pollination, flower size variation and floral symmetry

The pollinator-mediated stabilizing selection hypothesis suggests that the specialized pollination system of zygomorphic flowers might cause stabilizing selection, reducing their flower size variation compared to actinomorphic flowers. By using data on 43 species from two contrasting communities, Lázaro and Totland show that zygomorphic species that are highly dependent on pollinators and ecologically specialized are less variable in flower size than ecologically generalist and selfing zygomorphic species. However, these relationships are not found in actinomorphic species. The results suggest that the relationship between flower size variation and floral symmetry may be influenced by population-dependent factors, such as ecological generalization and species’...

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Virus-induced gene silencing and evo-devo studies in Cysticapnos

Virus-induced gene silencing and evo-devo studies in Cysticapnos

Gene silencing studies are increasingly being used to unravel the role of developmental genes. Hidalgo et al. report the establishment of virus-induced gene silencing (VIGS) in Cysticapnos vesicaria, a member of the fumarioid clade within the poppy family (Papaveraceae). They find that silencing of the PHYTOENE DESATURASE gene is very effective in all shoot organs, and successful silencing of a flower meristem gene is also demonstrated. The results make C. vesicaria a very promising new focus species for evolutionary–developmental studies, enabling comparative studies of flower symmetry, inflorescence determinacy and other traits that have diversified in the Papaveraceae.

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