The role of aspterric acid in auxin-regulated reproductive growth of Arabidopsis thaliana.

Application of 100 mu M aspterric acid (AA). a pollen growth inhibitor. with different concentrations of indole-3-acetic acid (IAA) results in the recovery of normal pollen development of Arabidopsis thaliana. Treatment with 100 mm AA plus 5 mM IAA significantly induced the normal seed production. Treatment with 100 mu M N-1-naphthylphthalamic acid (NPA), a polar auxin transport inhibitor, did not reduce the pollen growth but inhibited seed production. 100 mu M NPA plus 5 mM IAA did not induce any seed production. The endogenous level of IAA in sterns and leaves of A. thaliana treated with 100 mu M AA was similar to that of the untreated control. In contrast to AA treatment, the IAA level by the treatment With 100 mu M NPA,vas about twice as much as that of the untreated control. These results suggest that AA affects the Arabidopsis reproductive growth without inhibiting IAA biosyn-thesis and transport.