Evolutionary implications of C3–C4 intermediates in the grass Alloteropsis semialata

摘要: C4 photosynthesis is a complex trait resulting from series of anatomical and biochemical modifications to the ancestral C3 pathway. It thought evolve in stepwise manner, creating intermediates with different combinations -like components. Determining adaptive value these components key understanding how can gradually assemble through natural selection. Here, we decompose photosynthetic phenotypes numerous individuals grass Alloteropsis semialata, only species known include both genotypes. Analyses δ(13) C, physiology leaf anatomy demonstrate for first time existence physiological -C4 intermediate species. Based on previous phylogenetic analyses, are not hybrids between genotypes analysed, but instead belong distinct genetic lineage, might have given rise descendants. A. present colder climates, likely represents reversal state, indicating that, unlike photosynthesis, evolution phenotype irreversible.