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한국식물학회 / v.51, no.1, 2008년, pp.52-57 
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( Thermal Dissipation of Excess Light in Arabidopsis Leaves is Inhibited after Gamma-irradiation ) |
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| 초 록 |
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| To elucidate the effect of ionizing radiation on the non-photochemical quenching (NPQ) of chlorophyll fluorescence, we analyzed the buildup and release of NPQ in Arabidopsis wild-type (WT) and npql-2 mutant plants after gamma-irradiation. The npq1-2 mutant cannot normally induce the buildup of NPQ by a mutation in the violaxanthin de-epoxidase gene. A dose of $50;Gy;h^{-1}$ for 4 h significantly suppressed such buildup in the mutant and, more noticeably, in the WT. Both the initial rise and maximum level of NPQ were gradually inhibited after gamma-irradiation. In contrast, the release of NPQ and the maximum photochemical efficiency (Fv/Fm) of Photosystem II were largely unaffected in either genotype. This inhibition of NPQ buildup could be partly attributable to a significant decrease in the content of carotenoids, including xanthophyll pigments. Moreover, inhibition that was dependent on the xanthophyll cycle substantially enhanced the sensitivity of irradiated leaves to a photoinhibitory illumination of $800;{mu}mol$ photons $m^{-2};S^{-1}$. The difference in Fv/Fm values between the WT and npq1-2 under that photoinhibitory level of illumination was much smaller in the irradiated leaves than in the control. However, NPQ inhibition did not cause a significant difference in efficiency between WT and mutant when both were treated with UV-B irradiance of $2.4;W;m^{-2}$. Therefore, we suggest that a significant decrease in carotenoid content after gamma-irradiation should partially contribute to the enhanced sensitivity of irradiated plants, at least to high-light photoinhibition. This is accomplished by suppressing the thermal dissipation of excess light absorbed by photosynthetic pigments. |
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| 키워드 |
| gamma ray;high light;non-photochemical quenching (NPQ);ultraviolet (UV) ray;xanthophyll cycle; |
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Journal of Plant Biology / v.51, no.1, 2008년, pp.52-57
한국식물학회
ISSN : 1226-9239
UCI : G100:I100-KOI(KISTI1.1003/JNL.JAKO200810737042414)
언어 : 영어 |
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| 논문 제공 : KISTI 한국과학기술정보연구원 |
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