Effects of Brassin-Complex on Auxin and Gibberellin Mediated Events in the Morphogenesis of the Etiolated Bean Hypocotyl |
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| Authors: | JOHN H YOPP G CRAIG COLCLASURE NAGABHUSHANAM MANDAVA |
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| Institution: | Department of Botany. Southern Illinois University, Carbondale, Illinois 62901 and (N.M.) Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Beltsville Agricultural Research Center, Beltsville, Mayland 20705 |
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| Abstract: | The excised, hooked bean hypocotyl was the system used to determine wheiher the ‘auxin- and gibberellin like’ effect of the lipoidal pollen extract, Brass in-complex (Br), were mediated through, or independent of, auxin and gibberellin. The morphogenetic events of hook opening and hypocotyl elongation in this system are regulated by auxin and gibberellin, respectively. Brassin complex, like IAA, elicited a book closure in (he dark and retarded its opening in red light. This effect was synergized by T1BA, IAA and the presence of the auxin-producing organs, the epicotyl and cotyledons. Br-elicited hook closure was inhibited by the antiauxin. PCIB. Both GA3 and Br totally reversed the light inhibition of hypocotyl elongation. The GA3-effect, but nol the Br elicited elongation, was overcome by Ancymidol. Hypocotyl elongation was partially inhibited by TIBA and PCIB. suggesting a possible auxin involvement also in this effect of Br. Br may elicit its growth responses through an effect on endogenous auxin levels, In this way it is different from other lipoidat growth regulators, such as the oleanimins which require the presence of exogenous growth regulators for activity. |
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