| 青稞的光合特性及光破坏防御机制 |
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| 引用本文： | 程明,李志强,姜闯道,石雷,唐宇丹,张金政.青稞的光合特性及光破坏防御机制[J].作物学报,2008,34(10):1805-1811. |
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| 作者姓名： | 程明 李志强 姜闯道 石雷 唐宇丹 张金政 |
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| 作者单位： | 1.中国科学院植物研究所, 北京100093;2.中国科学院研究生院, 北京100039;3.北京市农业职业技术学院, 北京102442 |
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| 基金项目： | 中国科学院知识创新工程项目，中国科学院知识创新工程项目，中国科学院知识创新工程项目 |
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| 摘 要： | 通过气体交换、荧光猝灭动力学以及反射光谱等技术研究了两个青稞(Hordeum vulgare L.)品种的光合特性及激发能分配。结果表明, 青稞的光饱和点1 000 μmol m-2 s-1左右。在0~500 mmol m-2 s-1的光强范围里, 青稞叶片的光呼吸(Pr)随着光强升高而增加; 光强超过500 mmol m-2 s-1以后, 光呼吸变化不明显。光呼吸占总光合的比例(Pr/Pm)随光强增强下降。随着光强增强, 光系统II开放反应中心转化效率(Fv′/Fm′), 光系统II实际光化学量子效率(ΦPSII), 光化学猝灭系数(qP)不断降低而青稞叶片的非光化学猝灭(NPQ)持续升高, 说明越来越多的光能以热的形式耗散掉。光谱分析表明△PRI随着青稞叶片暴露于光下的时间迅速增大。因此, 光呼吸不是青稞主要的光破坏防御机制, 依赖叶黄素循环的热耗散可能是田间青稞耗散过剩光能的主要途径。
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| 关 键 词： | 青稞 强光 光呼吸 热耗散 |
| 收稿时间： | 2008-01-20 |
| 修稿时间： | 1900-01-01 |
Photosynthetic Characteristics and Photoprotective Mechanisms in Highland Barley |
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| CHENG Ming,LI Zhi-Qiang,JIANG Chuang-Dao,SHI Lei,TANG Yu-Dan,ZHANG Jin-Zheng.Photosynthetic Characteristics and Photoprotective Mechanisms in Highland Barley[J].Acta Agronomica Sinica,2008,34(10):1805-1811. |
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| Authors: | CHENG Ming LI Zhi-Qiang JIANG Chuang-Dao SHI Lei TANG Yu-Dan ZHANG Jin-Zheng |
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| Institution: | 1.Institute of Botany, Chinese Academy of Sciences, Beijing 100093;2.Graduate School of Chinese Academy of Sciences, Beijing 100049;3.Beijing Vocational College of Agriculture, Beijing 102442, China |
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| Abstract: | As a local crop of Qinghai-Tibet Plateau, highland barley (Hordeum vulgare L.) has acclimated to the typical habitat with strong light and low O2 to CO2 ratio. Low O2 to CO2 ratio may have a great influence on photorespiration which plays an important role in protecting photosynthetic apparatus against photoinhibition. In this study, we hope to know whether photorespiration plays an important role in photoprotection of highland barley and what are the main photoprotective mechanisms of highland barley. Gas exchange, fluorescence quenching kinetics and reflectance spectrum were investigated to explore the photosynthetic characteristic and allocation of excitated energy in two highland barley cultivars. Results showed that light saturation point of highland barley was about 1 000 μmol m-2 s-1. Photorespiration rate (Pr) increased with light intensity increasing while it did not change significantly above 500 mmol m-2 s-1. The percentage of photorespiration to total photosynthesis (Pr/Pm) declined gradually with the increase of light intensity. The efficiency of open centers of photosystem II (Fv’/Fm’), actual photosystem II efficiency (ΦPSII) and photochemical quenching (qP) all declined with the increase of light intensity; non-photochemical quenching increased with light intensity increasing, indicating that more and more excited energy dissipated as thermal dissipation. Spectrum analysis showed that the change of photochemical reflectance index (△PRI) increased significantly when fully dark-adapted plants were suddenly exposed to light. On these bases, we concluded that photorespiration is not the main pathway for highland barley to relieve strong light stress; thermal dissipation relying on xanthophyll cycle may play an important role in dissipating excessive excited energy in highland barley. |
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| Keywords: | Highland barley Strong light Photorespiration Thermal dissipation |
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