Chlorophyll formation in potato tubers as influenced by gamma irradiation and by chemicals

Summary

Gamma ray dosages of the order of magnitude of 10 kilorads inhibit the formation of chlorophyll in illuminated potato tubers. Increasing doses to 250 kilorads, while further decreasing chlorophyll formation, did not completely suppress it. Tubers treated with the lower doses retained their residual ability to develop chlorophyll upon illumination after a period of dark storage during which the non-irradiated controls lost a significant fraction of theirs. Of the three chemicals applied to the surface of potato tubers chloroisopropyl phenyl carbamate, O-methyl threonine, and 3-amino-1 2, 4-triazole, only the last named one inhibited the development of chlorophyll. Tubers obtained from plants whose leaves had been sprayed with maleic hydrazide developed as much chlorophyll as corresponding controls. Reflectance spectra of the exposed green surface of potato tubers suggest that carotenoid synthesis may be less sensitive to gamma irradiation than is the concomitant development of chlorophyll.