Effects of Gibberellic Acid on Hairy Root Growth in Datura innoxia

Abstract

Summary Cultures of Datura innoxia hairy roots transformed with Ri (root inducing) plasmid (pRi A4) were established after elimination of Agrobacterium rhizogenes. The hairy roots grew well with numerous lateral roots on a hormone-free MS medium. Exogenously applied gibberellic acid (GA3) at concentrations between 10 ng · 1-1 and 1 mg · 1-1accelerated the fresh weight increase of the hairy roots. Hairy root elongation and lateral branching were also enhanced by treatment with GA, Treatment with (E)-1-(4chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (S-3307), a specific inhibitor of gibberellin synthesis, inhibited the growth of hairy roots (fresh weight, elongation and lateral branching) at concentrations between 100 ng ·1-1 and 1·mg ·1-1. GA3 (10,µg· ·1-1) counteracted the inhibitory action of S-3307 (100 ng µ 1-1to 10 µg ·1-1) when both were simultaneously applied, and hairy root growth was restored to different degrees.