Analysis of flavone-flavonol ratio in Dicotyledoneae

The flavone-flavolol ratio (fo/fl) for Dicotyledoneae is studied through graphic comparisons between indices indicative of morphological tendencies: the herbaceousness and Sporne indices. These comparisons show a tendency toward the reduction of flavone biosynthesis in arboreous and shrubby taxa. Ligneous families (HI ≤150.0) and morphologically more primitive families (SI ≤55) possess fo/fl <1.OO. However, the relationship between evolutionary status of families with fo/fl values is not simply linear in Dicotyledoneae, because more advanced families are also characterized by a wider range of variation in fo/fl values.     

Endolithic chlorophyll d-containing phototrophs

Cyanobacteria in the genus Acaryochloris are the only known oxyphototrophs that have exchanged chlorophyll a (Chl a) with Chl d as their primary photopigment, facilitating oxygenic photosynthesis with near infrared (NIR) light. Yet their ecology and natural habitats are largely unknown. We used hyperspectral and variable chlorophyll fluorescence imaging, scanning electron microscopy, photopigment analysis and DNA sequencing to show that Acaryochloris-like cyanobacteria thrive underneath crustose coralline algae in a widespread endolithic habitat on coral reefs. This finding suggests an important role of Chl d-containing cyanobacteria in a range of hitherto unexplored endolithic habitats, where NIR light-driven oxygenic photosynthesis may be significant.