Published online by Cambridge University Press: 12 June 2017
The anatomy of the first internodes of three different lengths of giant foxtail (Setaria faberii Herrm.) was studied in the seedling stage. Epidermis was non-cutinized throughout the entire length. Least cortical breakdown occurred in an area 1 cm below the coleoptilar node, regardless of the length of internode. Endodermis and pericycle were present throughout the internode length, but identity was lost at the coleoptilar node and above. The number of metaxylem and protoxylem elements decreased basipetally from the coleoptilar node. Adventitious root primordia, found in all first internodes, originated from the pericycle. The total number of primordia, at the growth stage studied, appears to be proportional to the length of the internode, with fewer primordia in the 1-cm sections below the coleoptilar node. The implications of root and shoot uptake are discussed in terms of the anatomy of the first internode.