ROOT MORPHOGENESIS IN LEGUMES AND CEREALS AND THE EFFECT OF BACTERIALINOCULATION ON ROOT DEVELOPMENT

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