XVI International Botanical Congess
Salsola contains C3 and C4 species, and the structural and biochemical diversity of photosynthetic organs raises intriguing questions about the evolution of C4 photosynthesis from C3 ancestors. A molecular phylogenetic study was conducted based on ITS sequences of 41 C3 and C4 species from Salsola and related genera, and photosynthetic characters of leaves and cotyledons were scored for 25 species. Most species showed C4 photosynthesis in leaves, with diverse photosynthesis (including C3) in cotyledons. Species generally fall into clades that follow previous classifications and recent analysis of cotyledon features. C4 photosynthesis arose several times during the evolution of Salsola from at least three groups of C3 ancestors.