December 2000, Volume 42 Issue 12

 

          Research Articles
A Simple and Rapid Method to Determine the CO2/O2 Specificity Factor for Rubisco
Author: LI Guo-Fu, LU Wei, LI Sen, GONG Yan-Dao, ZHANG Xiu-Fang, ZHANG Rong-Xian, ZHOU Hai-Meng and ZHAO Nan-Ming
Journal of Integrative Plant Biology 2000 42(12): 1304-1307
      
    

A simple and rapid new method is presented to determine the CO2/O2 specificity factor for ribulose-1,5-bisphosphate(RuBP) carboxylase/oxygenase (Rubisco). In principle, the quantitative formula, which intrinsically resulted in error or enormous error in all reported methods, was improved to circumvent the problem. In practice, the complicated procedure with radiolabelling and chromatographic separation of 3-phosphoglycerate and 2-phosphoglycolate was substituted by one-step procedure without radiolabelling and chromatographic separation to decrease the random error. The effects of pH, temperature and ionic strength on accuracy of the data and the reliability of the calculation of the CO2/O2 specificity factor are also discussed.

一种简单快速测定Rubisco C02/O2特异性因子的方法
李国富1 陆巍2 李森1  公衍道1 张秀芳1 张荣铣2 周海梦1 赵南明1*

(1.  清华大学生物科学与技术系生物膜与膜生物工程国家重点实验室,北京100084;
2.  南京农业大学水稻研究所,南京210095)

摘要:提出了一种简单快速测定1,5-二磷酸核酮糖羧化/氧化酶CO2/O2特异性因子的方法.理论上改进了定量计算公式;操作上避免了使用放射性同位素标记以及层析分离3-磷酸甘油酸和2-磷酸乙醇酸的复杂程序,使测定过程一步完成,极大地减少了随机误差.讨论了实验数据(pH、温度、离子强度)的准确性对计算结果的影响.

关键词:1,5-二磷酸核酮糖羧化/ 氧化酶;CO2/02特异性因子;误差;准确性

Abstract (Browse 2070)  |  Full Text PDF       
Comparative Study on Photoinhibition Between Two Wheat Genotypes
Author: WANG Su-Wei, XU Chang-Cheng, BAI Ke-Zhi, ZHANG Qi-De, LI Liang-Bi, KUANG Ting-Yun, LI Ji-Yun and LI Zhen-Sheng
Journal of Integrative Plant Biology 2000 42(12): 1300-1303
      
    

Changes in the efficiency of the primary light energy conversion, fluorescence quenching parameters and contents of photosynthetic pigments were compared between two wheat (Triticum aestivum L.) genotypes in response to high light stress. The contents of chlorophyll and carotenoid in “Jing-411" were slightly higher than those in “Xiaoyan-54". Under high light stress, photoinhibition as indicated by a sustained decrease in PSⅡ photochemical efficiency was more pronounced in “Jing-411" than in “Xiaoyan-54". The content of ascorbate and the activity of the deepoxidase were higher in “Xiaoyan-54" than in “Jing-411". The genotypic difference in resistance to photoinhibition is related to the capacity to dissipate the excess energy nonradiatively. 

两个不同基因型小麦光抑制特性的比较
王肃威1  许长成1 白克智1 张其德1 李良璧1 匡廷云1* 李继云2  李振声3

(1. 中国科学院植物研究所光合作用基础研究开放实验室,北京100093;
2.  中国科学院生态研究中心,北京100085;3.  中国科学院遗传研究所,北京100101)

摘要:比较了两个不同基因型小麦(Triticum aestivum L.)"京411"和"小偃54"的原初光能转化效率、荧光猝灭参数和光合色素对强光胁迫的响应.在正常生长条件下"京411"的光合色素含量高于"小偃54";但在高光强下"京411"出现明显的光抑制,而"小偃54"对高光强的适应上优于"京411"."小偃54"适应高光强的原因是它在高光强下能大幅度地提高叶黄素循环的调控因子抗坏血酸的浓度及紫黄素脱环氧化酶(vDE)的活性,从而加速叶黄素循环对过多光能的耗散过程.

关键词: 光抑制;光合色素;叶黄素循环;小麦基因型

Abstract (Browse 1987)  |  Full Text PDF       
Enhancement of Photophosphorylation and Photosynthesis in Rice by Low Concentrations of NaHSO3 Under Field Conditions
Author: WANG Hong-Wei, WEI Jia-Mian, SHEN Yun-Gang, ZHANG Rong-Xian and YANG Tu-Nan
Journal of Integrative Plant Biology 2000 42(12): 1295-1299
      
    

Spraying 1-2 mmol/L solution of NaHSO3 on rice (Oryza sativa L.) leaves resulted in the enhancement of net photosynthetic rate for more than three days. It was also observed that NaHSO3 application caused increases both in ATP content in leaves and the millisecond-delayed light emission of leaves. The increase in net photosynthetic rate caused by NaHSO3 treatment was similar to that by PMS (phenazine methosulfate) treatment. The grain yield of treated rice was enhanced approximately by 10% after duplicated application of NaHSO3 in milk-ripening stage. It is suggested that the enhancement of photosynthesis by NaHSO3 treatment resulted from the effect of increasing ATP supplement. Concomitant with an increase in the photosynthetic rate and ATP content in leaves, the transient increase in chlorophyll fluorescence after the termination of actinic light, which could be used as an index of the cyclic electron flow, was also enhanced by low concentration of NaHSO3 treatment. Basing on these results it is proposed that the increase in rice photosynthesis caused by low concentrations of NaHSO3 could be due to the stimulation of the cyclic electron flow around PSⅠwhich in turn the enhancement of the coupled photophosphorylation and photosynthesis.

低浓度NaHSO 3促进田间水稻的光合磷酸化和光合作用
王宏炜1 魏家绵1  沈允钢1* 张荣铣2 杨图南3

(1. 中国科学院上海生命科学研究院植物生理研究所,上海00032;2.  南京农业大学水稻研究所,南京210095; 3. 江苏丘陵地区镇江农业科学研究所,江苏212400)

摘要:用1~2 mmol/L NaHSO3喷施于水稻(Oryza sativa L.)叶面可以提高叶片的光合速率,并能持续3 d以上.在此条件下,光下叶片中的ATP含量明显增高,叶片的叶绿素毫秒延迟荧光加强,反映与光合磷酸化活力有关的跨类囊体膜质子梯度增加.乳熟期喷施2次1 mmol/L NaHSO3后,水稻产量提高约10%.研究表明NaHSO3的主要作用和PMS(phenazine methosulfate)促进光合速率的原因可能类似,都是增加了ATP的供应.与此同时,观察到低浓度NaHSO3可促进水稻中反映循环电子传递的叶绿素荧光在作用光关闭后的短时上升.以上现象表明低浓度NaHSO3的促进作用很可能是通过促进围绕PSⅠ的循环电子传递及其耦联的光合磷酸化而促进水稻光合作用的.

关键词: 循环电子传递;毫秒延迟荧光;光合磷酸化;叶绿素荧光在作用光关闭后的短期上升

Abstract (Browse 2381)  |  Full Text PDF       
Study on a Mutant with Low Content Chlorophyll b in a High Yielding Rice and Its Photosynthesis Properties
Author: DAI Xin-Bin, CAO Shu-Qing, XU Xiao-Ming, LU Wei, ZHANG Rong-Xian, XU Chang-Cheng, CHEN Yao-Dong and KUANG Ting-Yun
Journal of Integrative Plant Biology 2000 42(12): 1289-1294
      
    

A high yielding rice mutant (Oryza sativa L. cv. Zhenhui 249) with low chlorophyll b was recently discovered in the field. The mutant was mainly characterized by the decrease of the content of extrinsic antennae complex. This variation was shown in the stage when the leaves were expanding. When the leaves are at the final developmental stage, the content would approach to that of the wild type. It was discovered that only moderate amount of chlorophyll b decreased in this mutant. The photosynthetic apparatus of the mutant was rather stable in the whole life span of the leaf. The extrinsic antennae complex of the mutant might make efficient use of light and meanwhile reduce the production of O2-.。

低叶绿素b高产水稻突变体及其光合特性的研究
戴新宾1  曹树青1 许晓明1  陆巍1 张荣铣1** 许长成2  陈耀东2  匡廷云2

(1.  南京农业大学水稻研究所,南京210095 ;2. 中国科学院植物研究所光合作用基础研究开放实验室,北京100093)


摘要:最近发现了一个在田间条件下自然产生的低叶绿素b高产水稻突变体(Oryza sativa L. cv.Zhenhui 249),该突变体主要降低了外周捕光天线复合体的含量.这种变化主要表现在叶片全展前后,到叶片发育后期则接近野生型.与以往所研究的突变体不同的是,该突变体叶绿素b含量仅适量减少,因而不影响类囊体膜的稳定性.突变体的光合机构在叶片一生中较稳定,这可能表明突变减少了光系统截获的光能,相对提高了光能的利用率,减少了O-2的产生.

关键词: 叶绿素b;突变体;水稻;衰老

Abstract (Browse 2099)  |  Full Text PDF       
Photosynthetic Characteristics of Two Superhigh-yield Hybrid Rice
Author: WANG Qiang, ZHANG Qi-De, JIANG Gao-Ming, LU Cong-Ming, KUANG Ting-Yun, WU Shuang, LI Cheng-Quan and JIAO De-Mao
Journal of Integrative Plant Biology 2000 42(12): 1285-1288
      
    

The photosynthetic functions and the sensitivity to photoinhibition were compared between two superhigh-yield hybrid rice (Oryza sativa L.) Liangyoupeijiu and X07S/Zihui 100, the newly developed from two parental lines and traditional hybrid rice Shanyou 63 developed from three parental lines. The results showed that, as compared to Shanyou 63, the net photosynthetic rate of Liangyoupeijiu and X07S/Zihui 100 was 9.1% and 11.9% higher, the transpiration rate was 37.4% and 31.4% lower, and their water use efficiency was 74.2% and 63.5% higher respectively. After strong light (2 000 μmol photons·m-2·s-1) treatment for 2 h, the photochemical quantum yield and the photochemical quenching increased by 37.0% and 18.0% respectively in Liangyoupeijiu, 28.3% and 46.2% in X07S/Zihui 100, but decreased a little in Shanyou 63. The non-photochemical quenching decreased in Liangyoupeijiu and X07S/Zihui 100 (about 50%) but increased greatly in Shanyou 63 (about 50%). Better photosynthetic functions, higher water use efficiency and stronger resistance to photoinhibition, may be the physiological basis for the super high-yield of the two hybrid rice under study.

超高产杂交稻光合特性的研究
王强1 张其德1* 蒋高明1 卢从明1  匡廷云1 吴爽2 李成荃2 焦德茂3

(1. 中国科学院植物研究所光合作用基础究开放实验室,北京100093;2. 安徽省农业科学院水稻研究所,合肥230031;3.江苏省农业科学院遗传生理研究所,南京210014)

摘要:比较了超高产杂交稻(Oryza sativa L.)X07S/紫恢100和两优培九与多年来大面积推广的杂交稻汕优63的光合功能和抗光胁迫能力.结果表明,超高产杂交稻X07S/紫恢100和两优培九的净光合速率(Pn)分别比汕优63高9.1%和11.9%,而其蒸腾速率(Tr)分别比汕优63低37.46%和31.42%,此外,其水分利用效率(WUE)分别比汕优63高出74.2%和63.5%;经强光(2 000μmol photons@m-2@s-1)处理2 h之后,X07S/紫恢100和两优培九的光系统Ⅱ光化学量子效率分别上升28.3%和37.0%,荧光光化学猝灭系数分别升高46.2%和18.0%,而汕优63的这两项参数值却变化很小;同时,X07S/紫恢100和两优培九的非光化学猝灭系数均下降50%左右,而汕优63则上升近50%,表明超高产杂交稻较高的光合能力、水分利用效率以及较强的抗光抑制能力可能是其高产的生理基础.

关键词: 超高产杂交稻;净光合速率;水分利用效率;光胁迫;荧光诱导动力学参数

Abstract (Browse 2254)  |  Full Text PDF       
Effects of High Light Stress on Chlorophyll-protein Complexes of Two Subspecies of Rice
Author: XIN Yue-Yong, FENG Li-Jie, XU Yi-Nong, JIAO De-Mao, LI Liang-Bi and KUANG Ting-Yun
Journal of Integrative Plant Biology 2000 42(12)
      
    
Abstract (Browse 1853)  |  Full Text PDF       
Physiological Basis of Photosynthetic Tolerance to Photooxidation and Shading in Rice
Author: LI Xia and JIAO De-Mao
Journal of Integrative Plant Biology 2000 42(12): 1271-1277
      
    

Thirty genotypes from rice germplasm were identified under photooxidation and shading condition and divided into four basic types : (1) cultivars tolerant to both photooxidation and shading, (2) cultivars tolerant to photooxidation but sensitive to shading, (3) cultivars tolerant to shading but sensitive to photooxidation, and (4) cultivars sensitive to photooxidation and shading. A comparative study of photosynthetic characteristics of a cultivar (cv. Wuyujing 3) that is tolerant and a cultivar (cv. Xiangxian) that is sensitive to both photoinhibition and shading showed that the photochemical efficiency of PSⅡ (Fv/Fm) and the content of PSⅡ-D1 protein in the tolerant cultivar “Wuyujing 3” decreased less under photoinhibition conditions as compared with “Xiangxian”. Under photooxidation conditions, superoxide dismutase was induced rapidly to a higher level and the active oxygen O- built up to a lower level in “Wuyujing 3” than in “Xiangxian”. At the same time, the photosynthetic rate decreased by 23% in “Wuyujing 3” vs. 64% in “Xiangxian”. Shading (20% natural light) during the booting stage caused only small decreases (7%-13%) in RuBisCO activity and the photosynthetic rate in “Wuyujing 3” but showed marked decreases (57%-64%) in “Xiangxian” which corresponded to the decreases in grain yield in the two cultivars (38% and 73%, respectively). The correlation analysis showed that the tolerance to photooxidation is mainly related to PSⅡ-D1 and that to shading is mainly related to RuBisCO activity. This study provided a simple and effective screening method and physiological basis for crop breeding in enhancing tolerance to both high and low radiation.

水稻耐光氧化和耐荫特性的生理基础
李霞 焦德茂*

(江苏省农业科学院农业生物遗传生理研究所,南京210014)

摘要:用简易、有效的人工光氧化和遮荫技术对30个水稻(Oryza sativa L.)种质进行筛选,鉴定出既耐光氧化又耐荫、耐光氧化不耐荫、耐荫不耐光氧化、既不耐荫又不耐光氧化等4种品种类型,并用既耐光氧化又耐荫的品种"武育粳3号"和对光氧化和遮荫均敏感的品种"香籼"进行光合特性研究.结果表明:在遮荫条件下,与对光氧化和遮荫敏感的品种"香籼"比较,"武育粳3号"的PSⅡ活性差异不大,RuBisCO活性降低较少,光合能力、光合生产力较高.在光抑制条件下,"武育粳3号"的PSⅡ活性,PSⅡ光化学效率(Fv/Fm),PSⅡ-D1蛋白含量降低较少,光合作用光抑制较轻.在光氧化条件下,内源活性氧清除剂SOD诱导活性高,清除O-能力强,因而叶绿素衰减较慢.上述研究为水稻育种提供了配套的优良生理特性的鉴定技术和生理依据.

关键词: 光氧化;遮荫;水稻;PSII!光化学效(Fv/Fm); Rubis CO

Abstract (Browse 2088)  |  Full Text PDF       
Effects of Membrane Lipids on the Electron Transfer Activity of Cytochrome b6f Complex from Spinach
Author: YAN Jiu-Sheng, MAO Da-Zhang, CHEN Hui, KUANG Ting-Yun and LI Liang-Bi
Journal of Integrative Plant Biology 2000 42(12)
      
    A lipid-depleted cytochrome b 6f (Cyt b 6f) preparation was obtained from spinach (Spinacia oleracea L.) chloroplasts. Upon reconstitution of this preparation with the membrane lipids purified from spinach thylakoid, the effects of different membrane lipids on the electron transfer activity were studied. The results show that the electron transfer activity of Cyt b 6f is obviously stimulated to different extents, respectively,bymonogalactosyldiacylglycerol(MGDG),digalactosyldiacylglycerol(DGDG), phosphatidylcholine (PC), phosphatidylglycerol (PG) and sulfoquinovosyldiacylglycerol (SQDG), and that the extents of stimulation may be closely related to the charge of the membrane lipids. The stimulation of non-charged lipids (MGDG, DGDG) and neutrally-charged lipid (PC) was high with a maximum enhancement of 89%, 75% and 77%, respectively; but the stimulation of two kinds of negatively-charged lipid (PG and SQDG) was relatively low with a maximum enhancement of 43% and 26%, respectively.
Abstract (Browse 1982)  |  Full Text PDF       
Membrane Lipids and Their Fatty Acid Composition in Nostoc flagelliforme Cells
Author: WANG Mei, XU Yi-Nong, JIANG Gui-Zhen, LI Liang-Bi and KUANG Ting-Yun
Journal of Integrative Plant Biology 2000 42(12)
      
    Nostoc flagelliforme Born. et Flah is highly adapted to drought stress, cold and light stresses, and suitable for growing in the unfavorable areas. This paper presents the results of the analysis of the membrane (mainly thylakoid membrane) lipids from N. flagelliforme in order to investigate the relationship between membrane lipid composition and stress resistance to this cyanobacteria. The membrane lipids are composed of monogalactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG), sulfoquinovosyl diacylglycerol (SQDG) and phosphatidylglycerol (PG). The major fatty acids in these lipids are palmitic (16∶0), palmitoleic (16∶1), stearic (18∶0), oleic (18∶1), linoleic (18∶2) and linolenic (18∶3) acids. In N. flagelliforme, polyunsaturated fatty acids account for 73% of the total fatty acids, much higher than that of the other cyanobacteria reported so far. Among which 16∶1 and 18∶3 are as high as 28.9% and 34.3% respectively. The high resistance of N. flagelliforme to abnormal conditions may be associated with the extent of unsaturation of fatty acids. In addition, the wild N. flagelliforme treated with water for 30 min and cultured for 24 h and the lipid and fatty acid composition were found to be not affected by water-absorption.
Abstract (Browse 2169)  |  Full Text PDF       
Structural Characteristics of Thicker-culms in the High-yield Wheat Cultivars
Author: LI Han-Bing, BAI Ke-Zhi, KUANG Ting-Yun, HU Yu-Xi, JIA Xu and LIN Jin-Xing
Journal of Integrative Plant Biology 2000 42(12)
      
    The culm of the Triticum aestivum L. cv. “Lankao 906-4”, a high-yield cultivar, in comparison with “Jing 411”, a widely-planted cultivar, was studied by means of anatomical technique coupled with mechanical and chemical theory. A anatomical analysis revealed that “Lankao 906-4” possessed thicker mechanical tissue and larger vascular bundle area than those of “Jing 411”. In terms of the resistance to lodging, “Lankao 906-4”had higher culm strength. Furthermore the content of lignin was semiquantitatively analyzed with confocal laser scanning mircoscope (CLSM), and revealed a much higher lignin content in the culm of “Lankao 906-4” than that in the culm of “Jing 411”. All of these indicated that the characteristics of culm were important factors in breeding the super-production wheat cultivar. 
Abstract (Browse 2222)  |  Full Text PDF       
Influence of Replacing Bacterial Pheophytin with Pheophytin on the Picosecond Fluorescence from Reaction Centers of Purple Bacteria
Author: ZOU Yong-Long, ZHAO Fu-Li, WANG He-Zhou, XIA An-Dong, ZENG Xiao-Hua and XU Chun-He
Journal of Integrative Plant Biology 2000 42(12): 1243-1248
      
    

Fluorescence spectra of native purple bacterial reaction center (RC) and bacterial pheophytin (Bphe) replaced RCs were obtained from 600 nm to 900 nm with a selective excitation at 597 nm. With the help of measuring the fluorescence from bacterial chlorophyll, bacterial pheophytin and plant pheophytin, the corresponding components in the RCs are classified for fluorescence emission. Results showed that pheophytin substitution influences the composition of fluorescence spectra. Therefore, four, three and two components were obtained from fluorescence spectra of native RC, Bphe B-replaced RC and Bphe A,B-replaced RC, respectively. Fluorescence components are well correlated to the binding of plant pheophytin. The decay of excited state of primary electron donor P in different RCs was also studied by measuring the fluorescence decay at 686.4, 674.1 and 681.1 nm, respectively. The decaying kinetics changed in different RCs, indicating that pheophytin replacement influenced the energy transduction and primary photochemical reaction in purple bacterial reaction centers.

去镁叶绿素置换细菌去镁叶绿素对紫细菌反应中心皮秒荧光的影响
邹永龙1 赵福利2 汪河洲2 夏安东2 曾小华1  徐春和1*

(1. 中国科学院上海生命科学研究院植物生理研究所,上海200032;
2. 中山大学超快速激光光谱学国家重点实验室,广州510270)

摘要:选择597 nm作为激发波长,探测范围为600~900 nm的荧光特性,分析了天然反应中心和两种去镁叶绿素置换的紫细菌反应中心的荧光发射光谱.借助细菌叶绿素、细菌去镁叶绿素和植物去镁叶绿素的荧光光谱,对相关组分进行了归类.实验结果表明选择性地置换细菌去镁叶绿素影响了荧光光谱的组成.在天然反应中心、BpheB置换的反应中心和BpheA,B置换的反应中心中可分别解析到4、3和2个荧光发射组分.研究肯定荧光发射组分与去镁叶绿素的结合存在对应关系.实验还分别在686.4、674.1和681.1 nm处测定了不同反应中心内的原初电子供体P的激发态通过荧光衰减的过程,观测到衰减动力学上的差异.说明去镁叶绿素置换影响了细菌反应中心内激发光能传递和原初光化学反应过程.

关键词: 去镁叶绿素置换;皮秒荧光;紫细菌;反应中心

Abstract (Browse 1952)  |  Full Text PDF       
Ultrafast Spectral Studies of the Primary Processes of Photosynthesis in Spinach and Water Hyacinth Leaves
Author: XU Si-Chuan, SUN Zhao-Yong, AI Xi-Cheng, FENG Juan, ZHANG Qi-Yuan, ZHANG Xing-Kang, YU Fei, TANG Chong-Qin and KUANG Ting-Yun
Journal of Integrative Plant Biology 2000 42(12): 1235-1242
      
    

The authors have studied the spectroscopic characteristics and the fluorescence lifetime for the chloroplasts from spinach (Spinacia oleracea L.) and water hyacinth (Eichhornia crassipes (Mart) Solms.) plant leaves by absorption spectra, low temperature steady-state fluorescence spectroscopy and single photon counting measurement under the same conditions. The absorption spectra at room temperature for the spinach and water hyacinth chloroplasts are similar, which show that different plants can efficiently absorb light of same wavelength. The low temperature steady-state fluorescence spectroscopy for the water hyacinth chloroplast reveals a poor balance of photon quantum between two photosystems. The fluorescence decays in PSⅡ measured at the natural QA state for the chloroplasts have been fitted by a three-exponential kinetic model. The slow lifetime fluorescence component is assigned to a collection of associated light harvesting Chl a/b proteins, the fast lifetime component to the reaction center of PSⅡ and the middle lifetime component to the delay fluorescence of recombination of P+680 and Pheo-. The excited energy conversion efficiency (η) in PSⅡ RC is 87% and 91% respectively for the water hyacinth and spinach chloroplasts calculated on the 20 ps model. This interesting result is not consistent with what is assumed that the efficiency is 100% in PSⅡ RC. The results in this paper also present a support for the 20 ps electron transfer time constant in PSⅡ RC. On the viewpoint of excitation energy conversion efficiency, the growing rate for the water hyacinth plan is smaller than that for the spinach plant. But, authors' results show those plants can perform highly efficient transfer of photo-excitation energy from the light-harvesting pigment system to the reaction center (approximately 100%).

水葫芦及菠菜光合作用原初光反应的超快光谱研究
徐四川1* 孙照勇1 艾希成1 冯娟1 张启元1 张兴康1 郁飞2 唐崇钦2 匡廷云2

(1. 中国科学院化学研究所分子科学中心分子动态与稳态结构国家重点实验室,北京100080;
2.  中国科学院植物研究所光合作用基础研究开放实验室,北京100093)

摘要:采用相同的分离技术,从水葫芦(Eichhornia crassipes (Mart)Solms.)和菠菜(Spinacia oleracea L.)叶片中提取叶绿体.利用吸收光谱和低温荧光光谱及皮秒荧光单光子计数技术对它们的光谱性质和光系统Ⅱ荧光寿命进行了研究.这两种叶绿体吸收光谱相似,暗示着它们都能高效吸收不同波长的光子.低温荧光光谱显示,水葫芦叶绿体两个光系统之间激发能分配平衡状态差,表明不利于该植物叶绿体高效利用吸收的光子能.采用三指数动力学模型对测定的光系统Ⅱ荧光衰减曲线拟合,水葫芦叶绿体光系统Ⅱ荧光衰减寿命分别是:138,521和1 494 ps;菠菜叶绿体荧光寿命分别是:197,465和1 459ps.并且归属了荧光组分,慢速度荧光衰减是由叶绿素堆积造成的,中等速度荧光衰减源于PSⅡ反应中心重新结合电荷组分,快速度荧光衰减归属于PSⅡ反应中心组分.基于20ps模型计算的水葫芦和菠菜叶绿体PSⅡ反应中心激发能转能效率分别是87%和91%.该结果与转能效率为100%的观点不一致.实验结果支持PSⅡ反应中心电荷分裂20 ps时间常数模型.根据转能效率,水葫芦生长速度不大于菠菜生长速度,但是,水葫芦叶绿体中含有丰富的胡萝卜素成分,其单位质量叶绿体吸收光能大于单位质量菠菜叶绿体吸收的量.实验结果还暗示植物叶绿体体系传能高效,接近于100%.

关键词: 水葫芦;菠菜;叶绿体;单光子计数;荧光寿命;转能效率

Abstract (Browse 2177)  |  Full Text PDF       
Preliminary Study on Electron Crystallography of 27 kD LHC-¢ò Complex from Cucumber
Author: ZHANG Xu-Jia, WANG Ling-Yun, HUANG You-Guo, WANG Ke-Bin and KUANG Ting-Yun
Journal of Integrative Plant Biology 2000 42(12): 1253-1257
      
    

Cucumber (Cucumis sativus L.) LHC-Ⅱ complex, which consists of only one subunit (27 kD), was isolated and purified. 2-D crystallization was performed by batch method. The crystal is 0.7 μm×1.0 μm, and diffracts to 30 ?. The projection map of the negatively stained two-dimensional crystal of LHC-Ⅱ complex shows that the crystal has p3 symmetry, lattice constant 15.4 nm×15.4 nm, which is different from the LHC-Ⅱ of spinach (Spinacia oleracea L.) and pea (Pisum satium L.). A continuous tomographic tilt series, containing 12 projections from the two-dimensional crystal was subjected to 3-D reconstruction. The 3-D model represents that LHC-Ⅱ complex consists of 6 monomers. These trimer and dimer interactions build up the sixmember ring. 

黄瓜27 kD LHC-II复合物三维结构的电子晶体学初步研究
张旭家1 王凌云1 黄有国1 王可玢2  匡廷云2

(1. 中国科学院生物物理研究所生物大分子国家重点实验室,北京100101;2. 中国科学院植物研究所,北京100093)


摘要:从黄瓜(Cucumis sativus L.)叶片中分离出只含有一种亚基(27 kD)的LHC-Ⅱ复合物.采用batch方法获得了其二维晶体,大小为0.7 μm×1.0μm,衍射能力达30 A.负染样品的二维投影结果表明,该晶体为p3对称性,晶胞参数为15.4 nm×15.4 nm,不同于以往报道的菠菜(Spinacia oleracea L.)或豌豆(Pisum satium L.)LHC-Ⅱ晶体,为另外一种晶型.采用tomography技术,收集了0°~-55°系列倾斜照片,进行三维重构.LHC-Ⅱ复合物是由6个单体组成的六元环,相邻2个单体分别从膜的两侧插膜,方向相反,在膜区靠疏水-疏水相互作用成二聚体,3个相同的二聚体相互连接成六元环.

关键词: LHC-II;电子晶体学;三维重构

Abstract (Browse 2144)  |  Full Text PDF       
Model Compounds of the Mn Cluster in Oxygen-evolving Complex of PS¢ò
Author: CHEN Chang-Neng, ZHU Hong-Ping, HUANG De-Guang and LIU Qiu-Tian
Journal of Integrative Plant Biology 2000 42(12): 1249-1252
      
    

Six model compounds have been synthesized and used for probing the structural features of the Mn cluster in oxygen-evolving complex (OEC) of photosystem Ⅱ (PSⅡ). The model compounds contain Mn2(μ-O) 2 and μ-O-μ-carboxylato di-manganese structural units, which offer Mn—Mn, Mn……Mn, and Mn—O(N) structural parameters consistent with the corresponding data of the OEC in PSⅡ, implying that the Mn cluster in OEC may possess similar structural features. Two model compounds containing halide anion have been used for discussing the binding of Cl- to Mn in PSⅡ. It is suggested that in the five S states, ligand exchange would lead to the ligation of chloride to Mn in the S states with Mn of higher valence.

PSII系统放氧复合物中的锰簇模型物
陈昌能 朱红平 黄德光 刘秋田*

(中国科学院福建物质结构研究所结构化学国家重点实验室,福州350002)


摘要:合成了6个模型化合物并用以探讨PSⅡ的放氧复合物(OEC)中Mn簇的结构特征.模型物包含Mn2(μ-O)2和μ-O-μ-羧桥联的二锰结构单元,这些单元中的Mn-Mn、Mn……Mn和Mn-O(N)结构参数与PSⅡ系统OEC的相应数据一致,暗示OEC中Mn簇可能具有类似的结构特点.还有两个模型物包含了卤素阴离子,它们被用于讨论PSⅡ中Cl-与Mn的联系.讨论认为,在5个PSⅡ的S态中,具有高价锰中心的S态较之其他S态更有可能因为配体交换而导致Cl-与Mn的配位

关键词: 光合系统;放氧复合物;模型物;锰簇合物

Abstract (Browse 2475)  |  Full Text PDF       
Purification and Spectral Characteristics of Cytochrome b-559 from Oxygen-evolving Photosystem ¢ò Core Complexes of Spinach and Rice
Author: XIN Yue-Yong, YU Fei, TANG Chong-Qin, LI Liang-Bi and KUANG Ting-Yun
Journal of Integrative Plant Biology 2000 42(12): 1225-1230
      
    

Cytochrome b-559 in photosystem Ⅱ reaction center was purified from spinach (Spinacia oleracea L.) and rice (Oryza sativa L.) by a rapid and simple procedure. Their low temperature fluorescence emission and excitation spectra, ultraviolet fluorescence spectra and absolute absorption spectra were presented. The author's purification methods, which enhanced the yield of pure protein and shorted the time for isolation, have several advantages: 1. use of oxygen-evolving PSⅡ core complexes as the starting material in order to avoid disturbing from other cytochromes; 2. isocratic elution of cytochrome b-559 from a DEAE-Sephacel column for eliminating the impurity and yielding the protein in pure state; 3. a simple column procedure for removal of excess Triton X-100. Purified cytochromes b-559 from these species have similar optical spectra and mobility during gel electrophoresis under native conditions. From the results of novel electrophoresis (Tricine-SDS-PAGE), cytochrome b-559 from both spinach and rice reveal two polypeptide bands (apparent molecular weight 9 kD and 4 kD, respectively). By measuring of 77 K fluorescence spectra, it was shown that for the purified cytochrome b-559 there were two excitation peaks at 439 nm and 413 nm, and two emission peaks at 563 nm and 668 nm. This is the first indication that Cyt b-559 is able to emit fluorescence and also transfer excited electrons to chlorophyll. By the use of ultraviolet fluorescence spectra, it was demonstrated for the first time that the location of Trp residue could be in the hydrophobic transmembrane region of cytochrome b-559.

菠菜和水稻细胞色素b-559的分离纯化及其光谱性质研究
辛越勇 郁飞 唐崇钦 李良璧 匡廷云*

(中国科学院植物研究所光合作用基础研究开放实验室,北京1000)


摘要:用一种快速简捷的方法从菠菜(Spinacia oleracea L.)和水稻(Oryza sativa L.)中分离纯化了光系统Ⅱ反应中心内的细胞色素b-559,并且研究了其低温可见光区荧光光谱、室温紫外区荧光光谱、吸收光谱以及电泳特性.该方法的主要特点:1.以放氧核心复合物为起始材料以避免其他细胞色素的干扰;2.选用DEAE-Sephacel为层析介质,用等度洗脱除去杂蛋白和叶绿素;3.用同一介质不同条件去除过量的去垢剂.从两种植物中分离纯化的Cyt b-559具有相似的吸收光谱,在非变性电泳中有相同的泳动特征.用修订的适用于分析小蛋白的Tricine-SDS-PAGE证明,从两种植物中分离得到的Cyt b-559都是由两个多肽亚基组成,它们的表观分子量分别为9 kD和4 kD.低温荧光光谱的结果表明,Crt b-559的荧光激发峰位为413nm和439 nm,荧光发射峰位在563 nm和668 nm,首次证明Cyt b-559可以发出荧光并将电子传递给叶绿素.首次通过Cyt b-559的紫外荧光光谱证明Trp残基位于该蛋白的疏水跨膜区内.

关键词: 细胞色素b-559;放氧核心复合物;Tricine-SDS-PAGE;光谱

Abstract (Browse 2280)  |  Full Text PDF       
Observation of Fundamental and High Order Raman Modes of |?-Carotenes in Pd OECC Thin Film by SERS
Author: LIU Yu-Long, LIU Jin-Quan, ZHU Ke, YANG Guo-Zhen, SHAN Ji-Xiu, LI Liang-Bi and K UANG Ting-Yun
Journal of Integrative Plant Biology 2000 42(12): 1231-1234
      
    

Raman spectra of purified oxygen evolution core complexes (Pd OECC) thin films on silver mirror substrates have been taken over the frequency range of 250-3100 cm-1 by surface enhanced Raman scattering (SERS). Besides the fundamental frequency modes of β-carotene in Pd OECC, many weak peaks are observed. According to the selection rules of overtone and combination bands, most of them are attributed to the second-order Raman spectra of β-carotene. Compared with the SERS of normal Pd OECC, the SERS of Pd OECC after strong illumination shows a decrease in scattering intensity and an increase in line widths, indicating changes of conformation and micro-environment of β-carotene. The results of SERS are consistent with the changes of absorption spectrum of Pd OECC induced by strong illumination. There are no changes that can be ascribed to new vibration bands, so it is deduced that Pd OECC on the silver mirror is identical to that in the solution. In summary, SERS proved a good method to study the photodamage mechanism of photosynthesis.

SERS观察在Pd OECC薄膜中B-胡萝卜素的基频和高阶拉曼模
刘玉龙1 刘金全1 朱恪1 杨国桢1 单际修2  李良璧2   匡廷云2

(1.  中国科学院物理研究所光物理开放实验室,北京100080;
2.  中国科学院植物研究所光合作用基础开放实验室,北京100093)

摘要:利用有极高检测灵敏度的表面增强拉曼散射(SERS)技术,对吸附在银镜表面上的浓度较低的纯化的放氧核心复合物(Pd OECC)薄层进行了频移在250~3 100 cm-1范围内的拉曼光谱测量,除得到β-胡萝卜素分子的基频拉曼振动模外,在高频端还得到了许多弱峰.根据泛音和组合谱带选择定则分析,这些振动模式来自β-胡萝卜素分子的高阶拉曼光谱.还进行了Pd OECC在强光破坏前后的SERS光谱研究.在强光照射下,β-胡萝卜素分子的SERS光谱的散射强度明显降低,且线宽增加,说明强光照射不但改变了β-胡萝卜素的构象,而且也改变了β-胡萝卜素分子所处的微环境.其结果与强光照射前后吸收光谱的变化一致.另外,没有观察到Pd OECC薄层与银镜相互作用的其他新振动峰或Pd OECC中其他振动峰峰型的变化,可见Pd OECC在银镜表面保持原来的状态.这证明SERS技术在光合作用光破坏机理研究中的可行性.

关键词: SERS;光合作用;光破坏;β-胡萝卜素;基频和高阶拉曼模

Abstract (Browse 2194)  |  Full Text PDF       
Comparison Between the Influences of Phosphatidylcholine and Triton X-100 on the Protein Secondary Structures and Oxygen-evolving Activity of Photosystem ¢ò
Author: RUAN Xiang, XU Qiang, MAO Hai-Bin, SHAN Ji-Xiu, GONG Yan-Dao, ZHANG Xiu-Fang, KUANG Ting-Yun and ZHAO Nan-Ming
Journal of Integrative Plant Biology 2000 42(12): 1220-1224
      
    

The structural and functional alterations within the PSⅡ membrane from phosphatidylcholine reconstitution and Triton X-100 (TX-100) treatment were studied by using Fourier transform-infrared (FT-IR) spectroscopic technique and oxygen electrode. Phosphatidylcholine reconstitution showed no significant effect on the protein secondary structures of PSⅡ membrane but an increase of the rate of PSⅡ-mediated oxygen-evolution. The phosphatidylcholine lipids with different length of acyl chains displayed different capabilities to stimulate oxygen-evolution. In contrast, perturbation of the bilayer lipids by TX-100 resulted in obvious changes of the protein secondary structures within the PSⅡ membrane and in the loss of the PSⅡ-mediated oxygen-evolving activity. The results indicate the importance of membrane integrity in maintaining the stability of the photosynthetic membrane proteins.

磷脂酰胆碱和Triton X-100对光系统II蛋白二级结构及放氧活性影响的比较
阮翔1 许强1 毛海滨1 单际修2 公衍道1 张秀芳1 匡廷云2 赵南明1*

(1. 清华大学生物科学与技术系生物膜与膜生物工程国家重点实验室,北京100084;
2.  中国科学院植物研究所光合作用基础研究开放实验室,北京100093)


摘要:采用傅立叶变换红外光谱技术 (FT-IR)和氧电极研究了磷脂酰胆碱和TritonX-10 0对光系统Ⅱ膜复合物的蛋白二级结构及放氧活性的影响。结果表明 ,磷脂酰胆碱对光系统Ⅱ膜复合物的蛋白二级结构没有显著的影响 ,但能引起放氧活性的提高 ,而且脂酰侧链长度不同 ,对放氧活性的促进程度也不一样。相比较而言 ,TX-10 0对膜脂的扰动却引起蛋白二级结构的明显改变 ,并能抑致放氧活性。结果说明 ,完整的膜结构对维持光合膜蛋白的稳定是非常重要的。

关键词: 光系统II;磷脂酰胆碱;Triton X-100;FT-IR;放氧活性

Abstract (Browse 2148)  |  Full Text PDF       
Simulation of the Photosynthetic Reaction Center with an Artificial Solar Cell Reaction to Generate Triplet Moleculevia Charge Recombination
Author: WENG Yu-Xiang, XU Jing-Zhou, PAN Jie, LIN Kai-Li, WANG Li and YANG Guo-Zhen
Journal of Integrative Plant Biology 2000 42(12): 1215-1219
      
    

The formation of triplet chlorophyll and carotenoid by radical pair recombination have been observed in the reaction centers of photosystems of bacteria and higher plants. This is an important process for the photoprotection of the reaction centers, for the dissipation of excessive energy by non-radiative decay of carotenoid triplet. Triplet generation by the same mechanism in an artificial system has rarely been observed, only a few cases were reported in donor-acceptor triad supermolecules. This is probably the first time report of the simulation of the generation of triplet by back electron transfer using dye-sensitized TiO2 solar cell reaction. Triplet states have been observed in all-trans-retinoic acid sensitized TiO2 colloid during the recombination of the trapped electron with the retinoic acid radical cation after photoexcitation. The intermediates were characterized by ns time-resolved spectroscopy.

太阳能电池反应模拟光合系统反应中心电荷复合形成三线态分子的过程
翁羽翔*  徐景周 潘洁 林开利 汪力 杨国桢
(中国科学院物理研究所,北京100080)

摘要:光合系统反应中心普遍存在电荷复合反应形成三线态分子的过程,并通过所形成的三线态β-胡萝卜素将剩余的能量经无辐射通道耗散给环境,实现光合系统的光保护功能.这一过程在人工合成系统中十分罕见,见诸报道的仅有少数由给体-受体组成的超分子体系.首次报道应用染料敏化TiO2胶体颗粒的人工太阳能电池反应,模拟光合系统三线态分子的形成过程,成功地观测到了视黄酸自由基正离子与TiO2表面束缚电子复合而形成的三线态视黄酸分子,并对其光谱和动力学过程进行了纳秒时间分辨光谱表征.

关键词: 光合反应;三线态;TiO2;视黄酸;瞬态吸收光谱

Abstract (Browse 2051)  |  Full Text PDF       
Orientation of Pigments in the Isolated Photosystem ¢ò Sub-core Reaction Center CP47/D1/D2/Cyt b-559 Complexes: A Linear Dichrosism Study
Author: HOU Jian-Min, Dominique DEJONGHE, SHAN Ji-Xiu, LI Liang-Bi and KUANG Ting-Yun
Journal of Integrative Plant Biology 2000 42(12)
      
    Linear dichroism (LD) spectroscopy is an important technique in the study of the orientation and organization of pigments in the photosynthetic membrane complexes in vivo and in vitro. In this work, the orientation of the pigments in the isolated photosystem Ⅱ (PSⅡ) sub-core reaction center complexes was analyzed and characterized by means of low temperature absorption and LD spectroscopy. The preparations containing different amounts of CP47 isolated from spinach (Spinacia oleracea L.) chloroplast were used in order to investigate the orientation of pigments in the PSⅡ sub-core CP47/D1/D2/Cyt b-559 (CP47/D1/D2) complexes. Chlorophyll a (Chl a) absorbing at 680 nm in CP47/D1/D2/Cyt b-559 complex showed an orientation of the Q y transition parallel to the membrane plane. It is proposed that there are two forms of β-carotene (β-Car) in CP47/D1/D2/Cyt b-559 complex, denoted as β-Car (Ⅰ)and β-Car (Ⅱ), with different orientations, β-Car (Ⅰ) at 470 and 505 nm is roughly parallel to the membrane plane, and β-Car (Ⅱ) at 460 and 490 nm seems to be perpendicular orientation. Upon the photoinhibitory experiment β-Car (Ⅱ) was found to be photosensitive and easily photodamaged. It also showed that the positive LD signal observed at 680 nm was quite complicated. This signal is tentatively attributed to P680 and some Chl a of antenna in CP47 protein based upon our measurements.
Abstract (Browse 2040)  |  Full Text PDF       
 

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