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APICAL DOMINANCE, POLARITY, AND ADVENTITIOUS GROWTH IN MARCHANTIA POLYMORPHA
Author(s) -
Binns A. N.,
Maravolo N. C.
Publication year - 1972
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1972.tb10141.x
Subject(s) - marchantia polymorpha , auxin , thallus , biology , apical dominance , gemma , cytokinin , regeneration (biology) , botany , endogeny , germination , shoot , microbiology and biotechnology , biochemistry , gene
Benzylaminopurine, indoleacetic acid, and the auxin inhibitors transcinnamic acid, triiodobenzoic acid, and dinitrophenol were employed to elucidate the role of apical dominance and hormones during regeneration of thalli and gemmae of Marchantia polymorpha L. The cytokinin suppressed normal gemma germination and led to the development of nodular, callus‐like growths. When removed from the influence of benzylaminopurine, the site and magnitude of normal thallus outgrowths varied with the length of time that the tissue had remained on the cytokinin‐containing medium. This aberrant germination was not influenced by the incorporation of indoleacetic acid into the medium. Exogenous auxin neither accelerated nor inhibited the regeneration of normal thallus growth on excised vegetative discs. Transcinnamic acid and dinitrophenol inhibited regeneration. Auxin reversed this suppression. Triiodobenzoic acid did not significantly affect regeneration. Autoradiographs demonstrated a pronounced accumulation of labelled auxin in the midribs and the acropetal regions of excised thallus discs. This evidence suggests that there is an endogenous, basipetal auxin gradient in Marchantia; that the maintenance of this gradient is vital to normal growth and regeneration of the thallus; and that high endogenous concentrations of cytokinin destroy this polarity by increasing the auxin‐synthesizing capacity of the tissue.