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光污染和光学天文台址保护 被引量:8
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作者 谭徽松 岑学奋 《天文学进展》 CSCD 北大核心 2002年第1期1-6,共6页
讨论了天光背景对光学天文台的影响,综述了造成光污染的主要途径,介绍了防止光污染的几个主要国际组织和国际上对天文台址的保护立法;提出了减少光污染的主要措施。为国内进行光学天文台址保护采取措施以至(国家的或者地方的)立法... 讨论了天光背景对光学天文台的影响,综述了造成光污染的主要途径,介绍了防止光污染的几个主要国际组织和国际上对天文台址的保护立法;提出了减少光污染的主要措施。为国内进行光学天文台址保护采取措施以至(国家的或者地方的)立法提供参考。 展开更多
关键词 污染 天空亮度 学天文台 白址保护 强迫光 人为 自然背景辐射
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Photochemical Efficiency of PSⅡ and Membrane Lipid Peroxidation in Leaves of indica and japonica Rice (Oryza sativa) Under Chilling Temperature and Strong Light Stress Conditions 被引量:18
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作者 季本华 朱素琴 焦德茂 《Acta Botanica Sinica》 CSCD 2002年第2期139-146,共8页
Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light ... Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light stress conditions. Results showed that D1 protein contents of PSⅡ in photosynthetic apparatus dropped, the generation of antheraxanthin (A) and zeaxanthin (Z) of xanthophyll cycle were inhibited partly, PSⅡ photochemical efficiency (F v/F m)and non-photochemical quenching (q N) were also decreased obviously. In addition, endogenous active oxygen scavenger—superoxide dismutase (SOD) reduced, superoxide anion radical (O -· 2) and malondialdehyde (MDA) accumulated, as a result, photooxidation of leaves occurred under chilling temperature and strong light stress conditions. Obvious differences in the changes of the above mentioned physiological parameters between indica and japonica rice were observed. Experiments in leaves treated with inhibitors under chilling temperature and strong light conditions showed that indica rice was more sensitive to chilling temperature with strong light and subjected to photooxidation more than japonica rice. Notable positive correlation between D1 protein contents and F v/F m or (A+Z)/(A+Z+V), and a marked negative correlation between F v/F m and MDA contents were obtained by regression analysis in indica and japonica rice during chilling temperature and strong light conditions. According to the facts mentioned above, it was inferred that PSⅡ photochemical efficiency(F v/F m) was the key index to forecast for the prediction of photooxidation under stress circumstances and the physiological basis were the synthetic capacity of D1 protein and the protection of xanthophyll cycle. 展开更多
关键词 D1 protein PSⅡ photochemical efficiency (F v/F m) membrane lipid peroxidation xanthophyll cycle RICE
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PSⅡ Photochemistry and Xanthophyll Cycle in Two Superhigh-yield Rice Hybrids, Liangyoupeijiu and Hua-an 3 During Photoinhibition and Subsequent Restoration 被引量:6
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作者 王强 张其德 +3 位作者 朱新广 卢从明 匡廷云 李成荃 《Acta Botanica Sinica》 CSCD 2002年第11期1297-1302,共6页
PSⅡ photochemistry and xanthophyll cycle during photoinhibition (exposed to strong light of 2 000 μmol photons·m -2 ·s -1 ) and the subsequent restoration were compared between two superhigh_yi... PSⅡ photochemistry and xanthophyll cycle during photoinhibition (exposed to strong light of 2 000 μmol photons·m -2 ·s -1 ) and the subsequent restoration were compared between two superhigh_yield rice hybrids (Liangyoupeijiu and Hua_an 3, the newly developed rice hybrids from two parental lines) and the traditional rice hybrid Shanyou 63 developed from three parental lines. The results showed that the maximal efficiency of PSⅡ photochemistry ( Fv/Fm ), the efficiency of excitation energy capture by open PSⅡ centers ( Fv′/Fm′ ), and the yield of PSⅡ electron transport ( Φ PSⅡ ) of the three rice hybrids decreased during photoinhibition. However, a greater decrease in Fv/Fm , Fv′/Fm′ , and Φ PSⅡ was observed in Shanyou 63 than in Liangyoupeijiu and Hua_an 3. At the same time, the components of xanthophyll cycle, antherxanthin (A) and zeathanxin (Z) increased rapidly while violaxanthin (V) decreased considerably. Both the rate of accumulation and the amount of A and Z in the two superhigh_yield rice hybrids were higher than that in Shanyou 63. The de_epoxidation state (DES) of xanthophyll cycle increased rapidly with the fast accumulation of A and Z, and reached the maximal level after first 30 min during photoinhibition. Of the three hybrids, the increasing rate of DES in Liangyoupeijiu and Hua_an 3 was higher than that in Shanyou 63. After photoinhibition treatment, the plant materials were transferred to a dim light (70 μmol photons·m -2 ·s -1 ) for restoration. During restoration, both chlorophyll fluorescence parameters and xanthophyll cycle relaxed gradually, but the rate and level of restoration in the two superhigh_yield rice hybrids were higher than those in Shanyou 63. Our results suggest that Liangyoupeijiu and Hua_an 3 had higher resistance to photoinhibition and higher capacity of non_radiative energy dissipation associated with xanthophyll cycle, as well as higher rate of restoration after photoinhibition, than Shanyou 63 when subjected to strong light. 展开更多
关键词 superhigh_yield rice hybrid PHOTOINHIBITION RESTORATION PSⅡ photochemistry xanthophyll cycle
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Modeling Study of the Impact of Heterogeneous Reactions on Dust Surfaces on Aerosol Optical Depth and Direct Radiative Forcing over East Asia in Springtime 被引量:1
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作者 LI Jia-Wei HAN Zhi-Wei 《Atmospheric and Oceanic Science Letters》 2011年第6期309-315,共7页
The spatial distributions and interannual variations of aerosol concentrations, aerosol optical depth (AOD), aerosol direct radiative forcings, and their responses to heterogeneous reactions on dust surfaces over Ea... The spatial distributions and interannual variations of aerosol concentrations, aerosol optical depth (AOD), aerosol direct radiative forcings, and their responses to heterogeneous reactions on dust surfaces over East Asia in March 2006-10 were investigated by utilizing a regional coupled climate-chemistry/aerosol model. Anthropogenic aerosol concentrations (inorganic + carbonaceous) were higher in March 2006 and 2008, whereas soil dust reached its highest levels in March 2006 and 2010, resulting in stronger aerosol radiative forcings in these periods. The domain and five-year (2006-10) monthly mean concentrations of anthropogenic and dust aerosols, AOD, and radiative forcings at the surface (SURF) and at the top of the atmosphere (TOA) in March were 2.4 μg m 3 13.1 lag m^-3, 0.18, -19.0 W m^-2, and -7.4 W m^-2, respectively. Heterogeneous reactions led to an increase of total inorganic aerosol concentration; however, the ambient inorganic aerosol concentration decreased, resulting in a smaller AOD and weaker aerosol radiative forcings. In March 2006 and 2010, the changes in ambient inorganic aerosols, AOD, and aerosol radiative forcings were more evident. In terms of the domain and five-year averages, the total inorganic aerosol concentrations increased by 13.7% (0.17 μg m^-3) due to heterogeneous reactions, but the ambient inorganic aerosol concentrations were reduced by 10.5% (0.13 lag m-3). As a result, the changes in AOD, SURF and TOA radiative forcings were estimated to be -3.9% (-0.007), -1.7% (0.34 W m^-2), and -4.3% (0.34 W m^-2), respectively, in March over East Asia. 展开更多
关键词 heterogeneous reaction aerosol concentra- tion aerosol optical depth radiative forcing East Asia
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