“…Regarding seedling shoot, hypocotyl elongation in the dark is due to both cell division and cell elongation in some species such as lettuce and sunflower (Galli , Heupel and Kutschera , Kutschera and Niklas ), while it is exclusively due to elongation of cells whose number is pre‐established in the embryo for others species, e.g. A. thaliana, M. truncatula and white lupin (Sánchez‐Bravo et al , Gendreau et al , Raz and Koornneef , Pierre et al ). It is noted that epidermis plays a crucial role in organ elongation, for leaves (MacAdam et al ) and for stem including hypocotyl (Kutschera and Niklas , Kutschera ).…”