Gibberellin Requirement for the Normal Growth of Roots

Abstract

Gibberellin (GA) strongly promotes shoot growth whereas it shows little effect on root elongation in GA-deficient dwarf plants (cf. Fig. 1) and in rosette plants.1 Although roots of dwarf maize and lettuce respond to exogenous GA in some experimental conditions,2,3 roots of these plants elongate normally without GA application. These phenomena suggest that roots do not require GA or require less GA than shoots. Thus, studies on the role of GA in root growth have been limited as compared with those in shoots.4–6 In order to evaluate GA requirements for root growth, the effects of the interaction of ancymidol7 and GA3 on the elongation growth of roots and shoots have been studied in lettuce seedlings and in dwarf and normal pea plants.