| The involucral bracts (IB or phyllaries) of the sunflower (Helianthus annuus L.) capitulum constitute an example of photosynthesizing organs that contribute to the photosynthesis budget during the generation of crop yield. The anatomy of IB was analyzed in two domesticated primitive sunfower genotypes, Havasupai and Hopi, in the sunflower line HA89B, in the wild Helianthus annuus ssp. annuus, in the sunflower male-fertile line R013 and in the commercial hybrid DKOP3845. Stomata and trichomes were counted on the adaxial and abaxial epidermis. In all cases, the IB showed a one-layered adaxial and abaxial epidermis, secretory ducts and parenchymatic cells with abundant chloroplast. The vascular system was similar to that of the nomophylls; however, their... |
