Die Abhängigkeit des Wachstums der Avena-Koleoptile und ihrer sogenannten Wuchsstoffproduktion vom Auxingehalt des Endosperms

Pohl, Reinhard

doi:10.1007/bf01909374

Cited by 52 publications

(17 citation statements)

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“…It has been suggested that the seed of cereals supplies IAA to the shoot (8,17,19). The results indicate that there is no substantial acropetal supply of IAA, at least for the apical region of the mesocotyl, but there may be some supply to the basal region.…”

Section: And Discussionmentioning

confidence: 87%

“…The primary leaves, for instance, appear able to supply relatively large amounts of IAA (10). There is also a possibility that the mesocotyl receives some IAA in free (8,17,19) or conjugated (6, 15) form from the seed. Ifregulation ofmesocotyl growth by IAA is to continue to be regarded as an example of hormone-mediated growth correlations, it is necessary, at least, to show that the IAA reaches it from elsewhere in the seedling.…”

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confidence: 99%

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Sources of Free IAA in the Mesocotyl of Etiolated Maize Seedlings

Iino

Carr²

1982

Plant Physiol.

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experimental evidence that mesocotyl growth is controlled by auxin originating in the coleoptile is contradictory, and further research is needed.The results of Iino and Caff (10) provide a reaffirmation of the classical concept of IAA production at the coleoptile tip. The mesocotyl, however, is unlikely to depend totally on the coleoptile tip for its IAA. The primary leaves, for instance, appear able to supply relatively large amounts of IAA (10). There is also a possibility that the mesocotyl receives some IAA in free (8,17,19) or conjugated (6, 15) form from the seed. Ifregulation ofmesocotyl growth by IAA is to continue to be regarded as an example of hormone-mediated growth correlations, it is necessary, at least, to show that the IAA reaches it from elsewhere in the seedling. The present study investigates the extent of the dependence of the maize mesocotyl on other parts of the seedling as sources of IAA.In 1928, Went (27) expressed the opinion that the growth of the mesocotyl is determined by a growth substance (later called auxin) which reached it from the tip of the coleoptile. This hypothesis was experimentally supported by van Overbeek,[23][24][25] who showed that inhibition of mesocotyl elongation due to a genetic factor (dwarfism) or external treatments, such as heat and light, is accompanied by a lower yield of diffusible auxin from the tip or the base of the coleoptile. He was also able to reverse the heatinduced inhibition by applying hetero-auxin (IAA) to the tip of the coleoptile (24). Went (27) and van Overbeek (24) cited Beyer's (3) finding, that decapitation of the oat coleoptile tip inhibits the mesocotyl elongation, in support of the hypothesis. With maize, a similar effect of decapitation was found by Inge and Loomis (12).Light-induced inhibition has been shown recently to be reversed by applied IAA (22).On the other hand, the auxin hypothesis has not always received support. Schneider (18), working on inhibition by light, concluded that 'if there is an indirect mechanism involving the mediation of another part of the plant, the mediation can hardly be by way of auxin.' Mer (13) also marshalled evidence from his many experiments to contradict the auxin hypothesis. The most striking evidence was the claim that decapitation of the coleoptile tip exerted no appreciable effect on the elongation of the oat mesocotyl, even though successive decapitations of the coleoptile were carried out to reduce the possibility of auxin production at the coleoptile stump, known (28) as 'regeneration of the physiological tip.' Dattary and Mer (5) further claimed to show that the effect of light or heat treatment on mesocotyl elongation is not accompanied by a fall in the auxin content of the mesocotyl. Thus, the ' Present address:

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Section: And Discussionmentioning

confidence: 87%

mentioning

confidence: 99%

Sources of Free IAA in the Mesocotyl of Etiolated Maize Seedlings

Iino

Carr²

1982

Plant Physiol.

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“…Seeds of Avena and Zea are known to be rich in auxin (Pohl, 1935(Pohl, , 1936Hemberg, 1955;Hamilton, Bandurski and Grigsby, 1961). The acidic ether-extractable fraction of Zea seeds contains IAA and other zones of auxin activity on chromatograms developed with ammoniacal isopropanol which are similar to those found in aqueous diffusates of coleoptile tips by Shen-Miller and Gordon; the major one has an i?p corresponding to that of P (Hemberg, 1958).…”

Section: Auxin In Guttation Fluidmentioning

confidence: 99%

“…Pohl (1935Pohl ( , 1936 produced evidence that the seed, which is rich in auxin, acted as a source of auxin which moved acropetally and accumulated at the coleoptile tip, but this possibility was rejected by Skoog (1937) who found that no auxin could be detected in agar blocks placed on the stumps of decapitated coleoptiles. He concluded that the seed was acting as the source of an auxin precursor which moved acropetally but that auxin itself did not move in this way.…”

Section: Introductionmentioning

confidence: 99%

“…The contention of Pohl (1935Pohl ( , 1936) that auxin moves acropetally from the seed and accumulates at the coleoptile tip is opposed only by Skoog's (1937) experiment which depends on the assumption that any auxin which might be moving acropetally will diffuse into an agar block on the stutnp of a decapitated coleoptile. Skoog's experiments, like most of the other classical work on coleoptiles, were carried out in standard Avena growth chambers with a relative humidity adjusted to minimize guttation (Went and Thimann, 1937).…”

Section: Introductionmentioning

confidence: 99%

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Do Coleoptile Tips Produce Auxin?

Sheldrake

1973

New Phytologist

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SUMMARYA re-examination of the evidence for auxin production by coleoptile tips reveals that it is not conclusive and that several important problems remain unresolved. The possibility that auxin and auxin precursors move acropetally in the xylem was tested by analysing guttation fluid from intact colcoptiles, decapitated coleoptiles and primary leaves of Avena sativa. In all cases two zones of auxin activity were detected on chromatograms of the acidic ether-soluble fraction, one of which corresponded to the RF of indol-3-yl acetic acid (IAA). Similar auxin activity was found in guttation fluid from seedlings of Zea mays, Triticum aestivuvi and IlorJeum vul^are.

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Die chemische Regulierung des Wachstums

Burström¹

1961

Growth and Growth Substances / Wachstum Und Wuchsstoffe

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Die Abhängigkeit des Wachstums der Avena-Koleoptile und ihrer sogenannten Wuchsstoffproduktion vom Auxingehalt des Endosperms

Cited by 52 publications

References 13 publications

Sources of Free IAA in the Mesocotyl of Etiolated Maize Seedlings

Sources of Free IAA in the Mesocotyl of Etiolated Maize Seedlings

Do Coleoptile Tips Produce Auxin?

Die chemische Regulierung des Wachstums

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