To study the auxin metabolism of etiolated oat seedlings a modification of the straight growth method of assaying hormones, using wheat coleoptile cylinders has been employed. Wheat coleoptiles detached from the endosperm are subjected to high and low temperature treatment, and exposure to dim red light during handling, prior to cutting from them the 10 mm cylinders used in the assay. Such cylinders grow less in sucrose-buffer solution than do those not so treated, but their response to externally applied IAA is not affected. In this way a very small amount of IAA ( 0.005,ug ) in 0.5 ml of sucrose-buffer can be detected with certainty. The auxin content of the wheat coleoptiles used to provide the cylinders for the assay has been investigated. Heating and chilling, employed either separately or in combination, destroys native hormone; the reduced growth of the cylinders may thus be accounted for. Exposure to dim red light for the period used in the experiments has little effect on hormone content. The growth of the mesocotyl and coleoptile of etiolated oat plants can be modified differentially by using a number of environmental conditions as follows Treatment Mesocotyl Coleoptile Carbon dioxide promotion depression Ethanol slight promotion depression Nitrates slight promotion promotion after 5th day Sucrose slight promotion strong depression Heating strong depression transient promotion Illumination strong depression transient promotion Samples of plants grown under these conditions were harvested on successive days in darkness and immediately frozen in solid carbon dioxide. They were then dissected without allowing them to thaw and auxins were extracted in cold ether; purified; chromatographed, and assayed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:602280 |
| Date | January 1963 |
| Creators | Dattaray, Pratima |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/13686 |
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