| I. Research Notes Temperature effect on plastid pigment accunlulation in mutants of Einkorn wheat K. YAMASHITA and M. SUGINO Biological Laboratory, Kyoto University, Kyoto, Japan Two types of chlorophyll mutants of Triticum monococcum, namely albino and carotina induced by the senior author by X-ray, have been used in the present investigation. Under normal conditions albino seedlings look red or white and carotina seedlings do orange with slightly green color. Both of those mutants are nonviable while their heterozygotes are viable and segregate green and albino or carotina in a ratio of 3 to 1. 1) Effect of temperature on the pigment accumulation in albino seedlings: Albino seedlings grown at higher temperature (above 15C) or under a short duration of low temperature lack chlorophylls (Table 1) and carotinoid pigments. Namely, the ether extract of the mutant leaves shows no absorption in the region of 340-700 micro of wave length. The red pigmentation in albino seedlings is anthocyanin, which is separated into washing water from etherial layer. The red pigmentation was observed more distinctly when the plant grew under a lower temperature or on the media with higher concentration of sucrose. When the seedlings germinated at 1C in 36 days or more, chlorophyll gigment was accumulated in the basal portiorr of leaves. The pigment accumulation was increased according to the duration in low temperature (Table 1) carotinoid pigment seemed also to be accumulated by low temperature treatment. 2) Effect of temperature on pigmentation in carotina seedling: Carotina seedlings contain chlorophyll pigment except chlorophyll b in addition to carotinoid pigment when grown under the temperature at 10C (Table 2). When, however, grown under the temperature higher than 20C visible green pigment was accumulated and the entire leaves became yellow green in color (Table 1). This green pigmentation was localized in the lower portion of leaves. When the seedlings grew under low temperature and were transferred to the higher temperature, for example 25C, the entire leaves became yellow green in a day. In order to compare the carotinoid pigment in ether extracts of carotina and normal leaves, chlorophylls were removed off by washing the extract with water according to the Schertz's method. Absortion spectra of the extract showed that there is not big difference in carotinoid content between carotina and normal leaves. 3) Culture of the mutant plants: Albino and carotina seedlings were cultured in a nutritional media containing 5 percent of sucrose aseptically in test tube. The mutant seedlings germinated at 1C in 60 days in darkness were placed in light under the temperature of 25 + or - 2C, and observation was made after about 96 days. In albino plants green pigment accumulation, which is localized on the basal portion of the leaves, occurs in the low temperature, but the plants can not sustain their growth. In carotina plants, the pigment accumulation occurs on the entire leaf in higher temperature condition so that they can sustain their growth longer than albino. |