Gravity-induced events such as amyloplast sedimentation and lateral auxin transport
were probed with cytoskeletal drugs in coleoptiles of rice (Oryza sativa L.). Amyloplast sedimentation was retarded by taxol. Lateral transport of auxin (3H-indoleacetic acid) was strongly inhibited by EPC (ethyl N-phenylcarbamate), but
only partially inhibited by taxol. 1 mM EPC reduced gravitropism while phototropism
was not affected. The findings suggest that microtubules may transduce pressure or
proximity of amyloplasts to the auxin exporter in the plasmalemma.
Amyloplasts - cytoskeletal drugs - gravitropism - lateral auxin transport - microtubules
- rice (Oryza sativa L.)