<Li> Gibberellins--Together with ethylene they promote crown primordia growth and elongation . Together with auxin they promote root elongation . Gibberellins also inhibit lateral root primordia initiation . </Li> <Li> Ethylene--Ethylene promotes crown root formation . </Li> <P> Early root growth is one of the functions of the apical meristem located near the tip of the root . The meristem cells more or less continuously divide, producing more meristem, root cap cells (these are sacrificed to protect the meristem), and undifferentiated root cells . The latter become the primary tissues of the root, first undergoing elongation, a process that pushes the root tip forward in the growing medium . Gradually these cells differentiate and mature into specialized cells of the root tissues . </P> <P> Growth from apical meristems is known as primary growth, which encompasses all elongation . Secondary growth encompasses all growth in diameter, a major component of woody plant tissues and many nonwoody plants . For example, storage roots of sweet potato have secondary growth but are not woody . Secondary growth occurs at the lateral meristems, namely the vascular cambium and cork cambium . The former forms secondary xylem and secondary phloem, while the latter forms the periderm . </P>

Which of the following is not a normal function of roots