TOXICITY OF SOME ALIPHATIC ALCOHOLS

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Abstract
A study was made of elongation of soy-bean roots and the ash content of the shoots of these plants with simple solutions of Ca(NO3)2 and the following alcohols: methyl, ethyl, normal propyl, isopropyl, normal butyl, isobutyl, secondary butyl, tertiary butyl, normal amyl, isoamyl, and normal hexyl. The single solutions varied in concentration from 0.0012 M to 0.06 M. With each total concentration 9 sets of alcohol proportions were tested. Soy-bean seedlings having roots with an initial length of about 8 mm. were placed in the culture solutions and grown in darkness. Each test was terminated when the roots in a standard solution had attained a length of 95 mm. Amounts of root elongation, expressed as percentages of the elongation in the standard solution were used as the basis for quantitative comparisons of the physiological effects of the culture solutions. Amounts of ash of shoots, expressed as percentages of the ash of shoots in standard solutions were also used. With the exception of the less toxic alcohols, the root elongation and ash content of shoots were lower in single alcohol solutions than in distilled water. Elongation was inversely related to concentration, but no simple rule applicable to every case can be formulated regarding the relationship of toxicity to concentration over the range of concentrations tested. Single solutions of ethyl alcohol and of Ca(NO3)2 at low concentrations exert a stimulating influence for increasing growth. At a concentration of 0.0012 M these afford a medium for growth better than that of a standard solution. This stimulating influence is less pronounced in the case of isobutyl and isopropyl alcohol. When root elongation is the criterion for growth, the order of toxicity (from least to most toxic) for moderate retardation (0.003 M) is as follows: isopropyl, methyl, ethyl, secondary butyl, Ca(NO3)2, normal butyl, isobutyl, tertiary butyl, normal amyl, normal propyl, isoamyl, and normal hexyl. For high retardation (0.06 M) the order is as follows: methyl, isopropyl, secondary butyl, Ca(N03)2, ethyl, normal butyl, isobutyl, normal propyl, tertiary butyl, normal amyl, isoamyl, and normal hexyl. When relative ash content is used as a criterion, the order of toxicity (from least to most toxic) for moderate retardation (0.03 M) is as follows: Ca(NO3)2, secondary butyl, ethyl, isopropyl, tertiary butyl, methyl, isoamyl, normal butyl, isobutyl, normal propyl, normal amyl, normal hexyl. At high retardation (0.06 M) the order is as follows: isopropyl, calcium nitrate, tertiary butyl, secondary butyl, methyl, ethyl, isobutyl, normal propyl, normal butyl, isoamyl, amyl, normal hexyl. Relatively more ash was found in shoots grown in a solution of 0.0012 M Ca(NO3)2 than in those grown in solutions of higher concentration. When seedlings were grown in mixtures of Ca(NO3)2 and methyl alcohol the solutions were not quite as toxic as when the components were used singly. When the individual alcohols, ethyl, normal propyl, normal butyl, and normal amyl were used in mixtures with Ca(NO3)2, the toxic effects were increased. This increase was most pronounced when normal amyl was used in mixtures with Ca(NO3)2. The toxicity of alcohols does not seem to increase regularly with increased number of C atoms in the molecules, Not in all instances is the normal alcohol more toxic than the iso-alcohol. Equations are given for computing approximate growths.