Root morphogenesis in legumes and cereals and the effect of bacterial inoculation on root development

Abstract

Root morphology is both genetically programmed and environmentally determined. We have begun an analysis into the components of root development by: (a) constructing a range of transgenic clover plants to assess some of the genetic programs involved as both roots and nodules are initiated and develop. These transgenic plants report on auxin activity, flavonoid synthesis and chitinase expression and suggest a role for flavonoids as regulators of auxin levels; and (b) determining in cereals the effect of both added auxin and specific microorganisms on the initiation and development of modified root outgrowths and lateral roots. Appropriate combinations of auxin, the nitrogen fixing Acetobacter diazotrophicus, and rice variety did give rise to some plants which grew slowly for over 12 months in a nitrogen-free medium.