Mechanical Inhibition of Hypocotyl Elongation Induces Radial Enlargement

Abstract
Excised elongating segments from 3-day-old soybean (Glycine max var. Wayne) seedlings radially enlarged when auxin-promoted elongation was mechanically inhibited. Growth was similar to segments treated with auxin plus cytokinin. This observation suggests that cytokinin does not necessarily directly “reorient” cell enlargement. Cytokinin-induced radial cell growth may be a secondary effect of cytokinin's inhibition of auxin-promoted elongation.