. The chemistry and mode of action of plant growth substances; proceedings of a symposium held at Wye College, University of London, July 1955. Plant regulators; Auxin; Growth (Plants). Investigation of natural auxins and growth inhibitors about equal parts of anhydrous acetonitrile and hexane or heptane. Under these conditions, lAA and IAN remain in the acetonitrile phase, as well as ethylindole acetate (lAE), although there might be, possibly, some losses of the latter compound. 3. Chromatographic purification—It was found that some of the coloured impurities of plant extracts are strongly a
. The chemistry and mode of action of plant growth substances; proceedings of a symposium held at Wye College, University of London, July 1955. Plant regulators; Auxin; Growth (Plants). Investigation of natural auxins and growth inhibitors about equal parts of anhydrous acetonitrile and hexane or heptane. Under these conditions, lAA and IAN remain in the acetonitrile phase, as well as ethylindole acetate (lAE), although there might be, possibly, some losses of the latter compound. 3. Chromatographic purification—It was found that some of the coloured impurities of plant extracts are strongly absorbed on paper, so that when a chroraatogram is eluted with ether, some of the coloured material remains on the paper. Two types of chromatographic purifications have been used: (a) The crude extract was first chromatographed in distilled HoO and dried. The initial spot was then cut off and the rest of the paper eluted with ether or absolute ethanol. (b) The crude extract was first chromatographed in ziopropanol (80) -|-ammonia (10)-{-water (10) (v/v) and dried. Then the initial spot was cut off and discarded, and the rest of the paper cut transversely in the middle. The lower portion then contains mainly the acid auxins and the upper one the neutral auxins which can be eluted and rechromatographed separately. During the purification procedure, there is always a possibility of loss of active material and alteration of labile compounds. It has been possible, however, to avoid any purification by using crude extracts of small quantities of plant material and a very sensitive bio-assay test. The procedure adopted will be described below. THE CHROMATOGRAPHIC PROCEDURE In order to obtain an initial spot as small as possible, the plant extract is applied on the starting line of the paper strip by means of a tuberculin syringe {Figure 4) in a stream of air to allow the rapid evaporation of the Figure 4- Tectinique used to obtain small initial spots on cliromatograms. The extract (
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Keywords: ., bookcentury1900, bookcollectionbiodiver, booksubjectgrowthplants
