Characterization of a rice mutant having an increased susceptibility to light stress at high temperature |
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Authors: | Takuichi Fuse Koh Iba Hikaru Satoh Mitsuo Nishimura |
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Affiliation: | Dept of Biology, Faculty of Science, Kyushu Univ., Fukuoka 812, Japan;;Inst. of Genetic Resources, Faculty of Agriculture, Kyushu Univ., Fukuoka 812, Japan. |
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Abstract: | The effect of light irradiation at high temperature was investigated in a rice mutant, spl-2 , which is sensitive to solar radiation. Dead spots appeared on the mutant leaves when cultured at a high temperature (40°C) under strong white-light illumination (15 W m−2). A similar damage was also observed in the wild-type leaves under the same conditions when the plants were preincubated in the dark for one day. Preillumination with weak light (6 W m−2) lessened the irradiation-induced damage in the wild-type. These observations suggest that in rice plants the acclimatization to weak light has a protective effect against strong irradiation at high temperature, and the spl-2 locus participates in the mechanisms of the acclimatization. The action spectrum for the irradiation-induced damage at the high temperature (40°C) in the spl-2 leaves indicated that the maximum damage occurred at around 480 nm and, in a lesser extent, at around 680 nm. Activity of the O−2− and H2O2−scavenging enzymes in the spl−2 leaves were almost the same or somewhat higher than those in the wild-type after irradiation with strong white light (15 W m−2) at 40°C, whereas the content of ascorbic acid in the spl−2 decreased significantly compared with the wild type. |
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Keywords: | Acclimatization to light high temperature Oryza sativa photoinhibition photosynthesis rice solar-radiation sensitive mutant |
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