The Multiple Roles of Arabinogalactan Proteins in Plant Development

Arabinogalactan proteins (AGPs) are: (a) structurally complex macromolecules composed of a polypeptide, large branched glycan chains, and lipid?; (b) markers of xylem development in Arabidopsis primary root?; (c) abundant extracellular matrix components in tobacco styles?; (d) ac- tive in tip growth of lily pollen tubes?; (e) able to promote somatic embryogenesis in carrot cell cultures?; (f) involved in programmed cell death in Arabidopsis cell cultures?; (g) present in Ancient Egyptian mummies and hieroglyphs?; (h) found in Mountain Dew2?; (i) active ingredients in Juzen-taiho-to, a Sino-Japanese herbal medicine?; (j) some of the above?; or (k) all of the above?