The apical hook develops immediately after seed germination and protects the apical meristem. The curvature of apical hook results from asymmetric cell elongation rates at opposite side of the bending hypocotyls. Since apical hook is not required for survival during growth of Arabidopsis seedlings under laboratory conditions, it is an excellent model system to take genetic and cell biological approaches to study mechanisms underlying differential cell elongation.

Plant cells are enclosed in a complex cell wall which not only functions as a protecting barrier but also as a mechanical signaling hub responding to external and endogenous cues controlling morphogenetic processes. It is well known that auxin-brassinosteroid (BR) cross talk regulates apical hook in Arabidopsis. Using cell biological, pharmacological, genetic and molecular approach we are trying to find out cell wall-auxin and BR regulation of differential cell elongation.