GrainGenes

II.4. Trimethylphosphate: A weak mutagen*.

T. J. Arnason. Department of Biology, University of Saskatchewan, Saskatoon, Canada

* Supported by the National Research Council of Canada.

Chlorophyll mutation frequency in Montcalm barley following treatment of grains with aqueous solutions of trimethylphosphate (TMP) is reported here. High doses, e.g. 5% TMP for 24 hours or 20% for 4 hours at 20°C can be used without reducing germination to the 50% level. Various concentrations and treatment times were tried. None resulted in high chlorophyll mutation frequencies, however, with large doses spike mutation rates were usually 2-5 times as high as the observed spontaneous rate. Some results following treatment with 5% TMP are shown in Table 1. Obviously TMP has here only weak mutagenic effects on embryos of germinating barley seeds.

Table 1. Chlorophyll mutation frequency in barley after TMP-treatment of seeds.

Kølmark (1956), using a back-mutation test (Neurospora) found TMP to be almost completely ineffective. However, Epstein et al. (1970) inferred from their results that male mice treated with TMP transmitted dominant lethal mutations to zygotes at levels significantly above those of the controls.

References:

Epstein, Samuel S., Willa Bass, Elsie Arnold and Yvonne Bishop. 1970. Science 168:584-586.

Kølmark, G. 1956. Compt. Rend. Trav. Lab. Carlsb. Ser. Physiol. 26:205220.

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