The Use of Dimethylsulfoxide as a Solvent in the Tobacco Bioassay for Cytokinins

Abstract

The use of dimethylsulfoxide as a solvent for synthetic purine and urea derivatives in the tobacco callus bioassay for cytokinin activity (10) has simplified the test procedure at two stages. First, the high solubility of these compounds in DMSO' has made it possible to test the less active materials, or those which are only slightly water-soluble, through a wide range of concentrations; secondly, full strength DMSO stock solutions act as sterilizing agents. Test compounds in DMSO solutions can be added directly to the cooling agar medium after autoclaving, thus avoiding destructive heating, and reducing the work, time, and equipment needed for the bioassay.In this laboratory DMSO was first employed as a solvent in the bioassay of diphenylurea. Bruce and Zwar (1) assay of an extensive series of urea derivatives which were added to the culture media as ethanolic solutions before autoclaving.Their preliminary tests indicated no alcohol toxicity (about 1 %c final strength) and no loss of activity as a result of the autoclaving process. However, in our experience there was a marked loss in activity when DPU was added before autoclaving, while its low solubility in water and also in alcohol precluded its assay in a full range of concentrations. DMSO effectively dissolved DPU, which could then be added to the medium in a small volume of solvent, to obtain concentrations in the medium as high as 20 jM for maximum growth, and 200 AzM for bud production.The highest concentration of DMSO which could be added to

Survival of Suspension-cultured Sycamore Cells Cooled to the Temperature of Liquid Nitrogen

“…Two cases are considered: (a) suppression of the growth due to DMSO remaining in the cells after washing (16), and (b) decrease in a considerable number of intact cells due to toxicity of these cryoprotective substances, especially DMSO. In the present experiment, the decrease in intact cells may be largely responsible for the growth suppression.…”

1,3-di(benzo[d]oxazol-5-yl)urea acts as either adventitious rooting adjuvant or xylogenesis enhancer in carob and pine microcuttings depending on the presence/absence of exogenous indole-3-butyric acid

“…The final concentration of DMSO in the in vitro culture medium did not exceed the one considered toxic (0.2 %, v/v) (Schmitz and Skoog 1970). The 5-BDPU and the 6-BDPU, synthesized as previously reported (Ricci et al 2006), were of analytical grade.…”

Effects of Thidiazuron on Cytokinin Autonomy and the Metabolism of N6-(Δ2-Isopentenyl)[8-14C]Adenosine in Callus Tissues of Phaseolus lunatus L.

“…Cytokinin-active compounds (zeatin and Thidiazuron) used for experiments in the second passage were dissolved in dimethyl sulfoxide (20) and added to the autoclaved flasks before the medium solidified. To extract metabolites, the tissues were homogenized in 2.5 parts (v/w) of cold 95% ethanol.…”