ABSTRACT
INTRODUCTION The basic functions of the root system are the uptake of water and mineral nutrients, anchorage and, sometimes, support (407-410). Roots are also concerned with the supply of cytokinins and gibberellins to the shoot system and commonly store starch. They sometimes are perennating organs (430) and may be modified in various other ways such as into contractile roots, pneumatophores (411, 412), prop roots (413), aerial absorptive roots (258), haustoria (441, 442), spines (414), and nitrogenfixing nodules (415). Roots also sometimes give rise to adventitious shoots (145).
