Hormones and Early In vitro Development of Epiphyllous Propagules on Bryophyllum calycinum

Karpoff, Arnold J.

doi:10.2307/2443139

Cited by 8 publications

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“…Other laboratories have previously reported that cytokinins stimulate plantlet outgrowth in pieces of B. calycinum leaf (Karpoff, 1982;Houck and Riesberg, 1983). As these experiments were done with pieces of leaf in organ culture rather than with whole leaves, they are consistent with the results from our laboratory.…”

Section: Comparison Of Present Results With Earlier Data From Other Lsupporting

confidence: 90%

“…A further difficulty was that the major plant hormones had not yet been discovered. The subject was taken up again later in the century after the discovery of some of the major plant hormones (Heide, 1965;Yazgan and Vardar, 1977;Karpoff, 1982;Houck and Riesberg, 1983). In analogy to apical dominance, auxins were considered to be likely candidates for the inhibition of plantlet development on leaves attached to the plant.…”

Section: Introductionmentioning

confidence: 99%

“…On the basis of these experiments he proposed that plantlet outgrowth was suppressed on the intact plant by a mechanism related to apical dominance. However, other laboratories studying Bryophyllum found only weak or no effects of indole acetic acid on plantlet development (Yazgan and Vardar, 1977;Karpoff, 1982). Thus, it remained uncertain if the suppression of plantlet formation on leaves attached to the plant is due to a mechanism similar to apical dominance, mediated by auxins, or to some other mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Cytokinins inhibit epiphyllous plantlet development on leaves of Bryophyllum (Kalanchoe) marnierianum

Kulka

2006

Journal of Experimental Botany

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When leaves of Bryophyllum marnierianum are detached from the plant, plantlets develop from primordia located at their margins. Leaves excised with a piece of stem attached do not produce plantlets. Severing the major leaf veins overcomes the inhibitory effect of the attached stem, indicating that the control agent is transmitted through the vascular system. A possible mechanism is that an inhibitory substance, possibly a known plant hormone, transported from the stem to the leaf, suppresses plantlet development. A number of hormones were tested for their ability to inhibit plantlet primordium development in whole isolated leaves. Auxins had no effect, indicating that apical dominance is not involved. The cytokinins zeatin, kinetin, and benzylaminopurine (BAP) strongly inhibited plantlet development, suggesting that they may be the or a factor involved in maintenance of plantlet primordium dormancy when the leaf is attached to the plant. This hypothesis was strongly supported by the finding that treatment of leaves attached to stems with a cytokinin antagonist (purine riboside) released the primordia from inhibition. In contrast to whole leaves, plantlet primordium development on leaf explants incubated on Murashige Skoog medium containing 3% sucrose was strongly stimulated by cytokinins. A possible explanation of these observations is that in whole leaves the cytokinin signal is transduced into an inhibitory signal whereas in the isolated primordium cytokinin has a direct stimulatory effect. The inhibitory cytokinin pathway must be dominant as long as the leaf is attached to the plant. A model is proposed which could explain these findings. This study points to a novel role of cytokinins in the maintenance of foliar plantlet primordium dormancy.

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Section: Comparison Of Present Results With Earlier Data From Other Lsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cytokinins inhibit epiphyllous plantlet development on leaves of Bryophyllum (Kalanchoe) marnierianum

Kulka

2006

Journal of Experimental Botany

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“…The latter type of species is convenient for studying the regulation of plantlet formation as the development can be induced at any time by leaf excision. During the last century plantlet development in B. calycinum (also known as the ‘Goethe plant’) was studied in a number of laboratories ( Goebel, 1902 , 1916 ; Loeb, 1915 ; Reed, 1923 ; Mehrlich, 1931 ; Freeland, 1933 ; Heide, 1965 ; Karpoff, 1982 ; Houck and Riesberg, 1983 ). It was found that when the leaf is plucked, plantlets develop from primordia pre-formed at the leaf margin ( Howe, 1931 ; Naylor, 1932 ; Yarbrough, 1932 , 1934 ).…”

Section: Introductionmentioning

confidence: 99%

Hormonal control of root development on epiphyllous plantlets of Bryophyllum (Kalanchoe) marnierianum: role of auxin and ethylene

Kulka

2008

Journal of Experimental Botany

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Epiphyllous plantlets develop on leaves of Bryophyllum marnierianum when they are excised from the plant. Shortly after leaf excision, plantlet shoots develop from primordia located near the leaf margin. After the shoots have enlarged for several days, roots appear at their base. In this investigation, factors regulating plantlet root development were studied. The auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) abolished root formation without markedly affecting shoot growth. This suggested that auxin transport from the plantlet shoot induces root development. Excision of plantlet apical buds inhibits root development. Application of indole-3-acetic acid (IAA) in lanolin at the site of the apical buds restores root outgrowth. Naphthalene acetic acid (NAA), a synthetic auxin, reverses TIBA inhibition of plantlet root emergence on leaf explants. Both of these observations support the hypothesis that auxin, produced by the plantlet, induces root development. Exogenous ethylene causes precocious root development several days before that of a control without hormone. Ethylene treatment cannot bypass the TIBA block of root formation. Therefore, ethylene does not act downstream of auxin in root induction. However, ethylene amplifies the effects of low concentrations of NAA, which in the absence of ethylene do not induce roots. Ag2S2O3, an ethylene blocker, and CoCl2, an ethylene synthesis inhibitor, do not abolish plantlet root development. It is therefore unlikely that ethylene is essential for root formation. Taken together, the experiments suggest that roots develop when auxin transport from the shoot reaches a certain threshold. Ethylene may augment this effect by lowering the threshold and may come into play when the parent leaf senesces.

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Hormonal Regulation of Epiphyllous Bud Release and Development in Bryophyllum Calycinum

Houck

1983

American J of Botany

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The effects of various concentrations of several auxins and cytokinins separately and in combination on epiphyllous budding of Bryophyllum calycinum were investigated, using a marginal leaf strip method. The number of buds released per leaf in 10−6 m benzyladenine (BA) was 2.8 times greater than those in water, and 1.6 times greater in 10−5 m isopentyladenine (IPA). BA, IPA and kinetin were antagonistic to indoleacetic acid (IAA) or naphthaleneacetic acid (NAA) when used in combination treatments. The IAA oxidase co‐factor p‐coumaric acid (PCA) increased the number of epiphyllous buds to twice that of the water controls. This stimulatory effect of PCA on bud release suggests that an increase in IAA oxidase activity may be one of the significant changes that precedes the release of epiphyllous buds.

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Hormones and Early In vitro Development of Epiphyllous Propagules on Bryophyllum calycinum

Cited by 8 publications

References 0 publications

Cytokinins inhibit epiphyllous plantlet development on leaves of Bryophyllum (Kalanchoe) marnierianum

Cytokinins inhibit epiphyllous plantlet development on leaves of Bryophyllum (Kalanchoe) marnierianum

Hormonal control of root development on epiphyllous plantlets of Bryophyllum (Kalanchoe) marnierianum: role of auxin and ethylene

Hormonal Regulation of Epiphyllous Bud Release and Development in Bryophyllum Calycinum

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