• Korean Journal of Plant Tissue Culture
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• v.22 no.6
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• pp.345-350
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• 1995

Root gravitropism was investigated in the pea (Pisum sativum L.) mutant ageotropum lacking normal gravitropic response. Exogenous ethylene treatment inhibited gravitropic response in the normal (wild type) pea rook, but had no significant effect to restore the unresponsiveness in the mutant Neither inhibitors of ethylene biosynthesis nor antagonists of ethylene action were able to bring about the development of gravioopic curvature in the ageotropum roots. Auxin action seems to be normal since asymmetric application of agar blocks containing auxin to the mutant roots caused normal gravitropic response to occur. Endogenous as well as auxin-induced ethylene production in tissue segments of the mutant root was about equal to that of the wild type. However no appreciable lateral transport of labeled auxin was observed in glavistimulated mutant roots whereas typical auxin asymetry was apparent in the wild type roots under the same conditions. It is concluded that the mutant has a defect in either gravity perception or its transduction, but not in the effector system involving auxin action.