检索结果-南通市图书馆

低温和干旱双重胁迫对紫花苜蓿叶片光系统II的影响

在线全文

学校读者我要写书评

暂无评论

草地学报 2024年

作者：赵尧尧刘美君张政王婕王玉祥安长奇王跳霞新疆农业大学草业学院西部干旱区草地资源与生态教育部重点实验室新疆草地资源与生态重点实验室

新疆紫花苜蓿(Medicago sativa L.)在返青期常遭受低温和干旱双重胁迫。本研究以新疆主栽品种‘新牧4号’为材料，研究低温和干旱双重胁迫对苜蓿叶片光系统II(psii)的影响。以商业种‘WL525HQ’为对照，进一步分析双重胁迫对不同低温抗... 详细信息

新疆紫花苜蓿(Medicago sativa L.)在返青期常遭受低温和干旱双重胁迫。本研究以新疆主栽品种‘新牧4号’为材料，研究低温和干旱双重胁迫对苜蓿叶片光系统II(psii)的影响。以商业种‘WL525HQ’为对照，进一步分析双重胁迫对不同低温抗性的苜蓿psii具体的影响位点。结果表明：低温下psii最大光化学效率(Fv/Fm)、单位反应中心捕获的用于电子传递的能量(ETO/RC)显著降低，OJIP曲线中J点荧光上升，表明低温导致psii活性下降是由于受体侧和反应中心受损；干旱导致Fv/Fm显著降低，OJIP曲线中J、K、L点荧光上升且重度干旱导致单位反应中心吸收的光能(ABS/RC)、单位反应中心捕获的用于还原QA的能量(TRO/RC)、单位反应中心耗散掉的能量(DIO/RC)增加，表明干旱导致psii活性下降是由于psii供/受体侧、复合体受损及重度干旱psii反应中心受损；双重胁迫诱导产生的顺-3-乙烯醇可缓解单一胁迫对psii的伤害程度；在秋眠级较低的‘新牧4号’中，双重胁迫可缓解干旱对psii供体侧的伤害，在‘WL525HQ’中，双重胁迫可缓解低温对psii反应中心及受体侧的伤害，同时缓解干旱对psii供体侧、反应中心的伤害。

关键词：紫花苜蓿 psii 低温胁迫干旱胁迫双重胁迫

Early stage toxicity of excess copper to photosystem II of Chlorella pyrenoidosa–OJIP chlorophyll a fluorescence analysis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2009年第11期21卷 1569-1574页

作者： XIA Jianrong TIAN Qiran School of Environmental Science and Engineering Guangzhou University Guangzhou 510006 China Marine Biology Institute Shantou University Shantou Guangdong 515063 China

Acute toxicity of excess Cu on the photosynthetic performance of Chlorella pyrenoidosa was examined by using chlorophyll a fluorescence transients and JIP-test after exposure to elevated Cu concentrations for a short time period. High Cu concentration resulted in a significant suppression in photosynthesis and respiration. The absorption flux （ABS/RC） per psii reaction center increased with increasing Cu concentration, but the electron transport flux （ET0/RC） decreased. Excess Cu had an insignificant effect on the trapping flux （TR0/RC）. The decline in the efficiency, with which a trapped exciton can move an electron into the electron transport chain further than QA-（Ψ0）, the maximal quantum yield of primary photochemistry （φP0）, and the quantum yield of electron transport （φE0） were also observed. The amount of active psii reaction centers per excited cross section （RC/CS） was also in consistency with the change of photosynthesis when cells were exposed to excess Cu concentration. JIP-test parameters had a good linear relationship with photosynthetic O2 evolution. These results suggested that the decrease of photosynthesis in exposure to excess Cu may be a result of the inactivation of psii reaction centers and the inhibition of electron transport in the acceptor side.

关键词： Chlorella pyrenoidosa chlorophyll a fluorescence Cu psii

Structural Insights into Substrate Selectivity, Catalytic Mechanism,and Redox Regulation of Rice Photosystem Ⅱ Core Phosphatase

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2019年第1期12卷 86-98页

作者： Xiuying Liu Jingchao Chai Xiaomin Ou Mei Li Zhenfeng Liu National Laboratory of Biomacromolecules CAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences Beijing 100101P.R.China University of Chinese Academy of Sciences Beijing 100049P.R.China

Photosystem Ⅱ (psii)core phosphatase (PBCP)selectively dephosphorylates psii core proteins including D1,D2,CP43,and PsbH.PBCP function is required for efficient degradation of the D1 protein in the repair cycle of psii,a supramolecular machinery highly susceptible to photodamage during oxygenic photosynthesis.Here we present structural and functional studies of PBCP from Oryza sativa (OsPBCP).In a symmetrical homodimer of OsPBCP,each monomer contains a PP2C-type phosphatase core domain,a large motif characteristic of PBCPs,and two Small motifs around the active site.The large motif contributes to the formation of a substrate-binding surface groove,and is crucial for the selectivity of PBCP toward psii core proteins and against the light-harvesting proteins.Remarkably,the phosphatase activity of OsPBCP is strongly inhibited by glutathione and H202.S-Glutathionylation of cysteine residues may introduce steric hindrance and allosteric effects to the active site.Collectively,these results provide detailed mechanistic insights into the substrate selectivity,redox regulation,and catalytic mechanism of PBCP.

关键词： psii core phosphatase structure substrate selectivity redox regulation psii repair cycle

Molecular Functions of Oxygen-Evolving Complex Family Proteins in Photosynthetic Electron Flow

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2010年第8期52卷 723-734页

作者： Kentaro Ifuku Seiko Ishihara Fumihiko Sato Graduate School of Biostudies Kyoto University

Oxygen-evolving complex （OEC） protein is the original name for membrane-peripheral subunits of photosystem （PS） II. Recently, multiple isoforms and homologs for OEC proteins have been iden- tified in the chloroplast thylakoid lumen, indicating that functional diversification has occurred in the OEC family. Gene expression profiles suggest that the Arabidopsis OEC proteins are roughly categorized into three groups： the authentic OEC group, the stressresponsive group, and the group including proteins related to the chloroplast NAD（P）H dehydrogenase （NDH） complex involved in cyclic electron transport around PSI. Based on the above gene expression profiles, molecular functions of the OEC family proteins are discussed together with our current knowledge about their functions.

关键词： NDH Molecular Functions of Oxygen-Evolving Complex Family Proteins in Photosynthetic Electron Flow OEC psii PPL

Double Temperature and Density Phenomenon in Grid Enhanced Plasma Source Ion Implantation for Inner Surface Modification of Tubes

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2009年第5期11卷 555-559页

作者：张谷令王久丽贾莹邹斌杨思洋 School of Sciences Central University for Nationalities Institute of Physics Chinese Academy of Sciences

Inner surface coating for tubular samples was realized by the grid enhanced plasma source ion implantation （GEpsii） method. In the GEpsii system, two electrodes, a central rod electrode and a coaxial grid electrode were coaxially assembled inside the tube. Plasma was generated between the electrodes by a radio-frequency （RF） oscillating power source. Plasma then diffused through the grid and realized inner surface ion implantation by a negative high voltage applied to the tube. The plasma was then divided, by the grid, into two regions, namely the source plasma region and the diffused plasma region. The plasma＇s self-bias between two RF power source electrodes was measured. At the same time, the electron temperature and plasma density in the GEpsii system were measured by a scattering spectrometer. Results showed that the plasma properties of the two regions were entirely different; the plasma self-bias, which might greatly affect the sputtering rate of the central titanium electrode, depended on the electrode structure, gas pressure and RF power.

关键词： psii grid inner surface TiN

Fast acclimation of phytoplankton assemblies to acute salinity stress in the Jiulong River Estuary

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2019年第8期38卷 78-85页

作者： Gang Li Key Laboratory of Tropical Marine Bio-resources and Ecology & Guangdong Provincial Key Laboratory of Applied Marine Biology South China Sea Institute of Oceanology Chinese Academy of Sciences

Mixing of freshwater and seawater creates the well-known salinity gradients along the estuaries. In order to investigate how phytoplankton respond to the acute salinity changes, we exposed natural phytoplankton assemblies from the Jiulong River Estuary to differential saline field water while continuously monitoring their photosynthetic performances under both indoor-and outdoor-growth conditions. When the natural cell assemblies from salinity 30 field water were exposed to series low saline field water(salinity 25, 17, 13 and 7.5), the effective Photosystem II quantum yield(ΔF/Fm′) decreased sharply, e.g., to one-fifth of its initials after 5 min exposure to salinity 7.5 field water, and then increased fast during the following 40 min and almost completely recovered after 320 min. During such an exposure process, non-photochemical quenching(NPQ) sharply increased from 0 to 0.85 within 5 min, and then decreased to nearly 0 within the following 70 min. When these cells re-acclimated to salinity 7.5 field water were exposed to series high saline field water(salinity 13, 17, 25 and 30), a similar response pattern was observed, with the decreased ΔF/Fm′ accompanied with increased NPQ, and followed by the recovery-induced increase in ΔF/Fm′ and decrease in NPQ. A similar response pattern as ΔF/Fm′to the acute osmotic stress was also observed in the photosynthetic carbon fixation capacity according to radiocarbon(14C) incorporation. Our results indicate that estuarine phytoplankton assemblies could rapidly recover from the acute osmotic stress, implying a potential cause for their frequent blooms in coastal-estuarine waters where despite drastically varying salinity, available nutrients are abundant due to the land-derived runoffs or mixing-caused relaxations from sediments.

关键词： psii quantum yield carbon fixation salinity gradients phytoplankton assemblies Jiulong River Estuary

Research progress in the inner surface modification of metal tubes by plasma processing

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第11期16卷 1119-1126页

作者： ZHANG Guling~ 1,2 **, WU Xingfang~1, GU Weichao~2, CHEN Guangliang~2, FENG Wenran~2, NIU Erwu~2, LI Li~2, L Guohua~2, CHEN Huan~2, FAN Songhua~2, LIU Chizi~2 and YANG Size~2(1. School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China 2. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China) School of Material Science and Engineering University of Science and Technology Beijing Beijing 100083 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

The recent progress in inner surface hardening of tubes by plasma processing is summerized. Several techniques of inner surface plasma source ion implantation and deposition are introduced, and their advantages and disadvantages are discussed. The basic principles, technical features and new progress of inner surface plasma source ion implantation methods for metal tubes, which were developed in our laboratory, are described in detail. And perspectives of the future technical development for inner surface ion implantation of tubes are presented.

关键词： psii metal tubes inner surface surface modification.

不同光照强度对两份五味子资源psii活性的影响

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

西南农业学报 2022年第12期35卷 2788-2793页

作者：郭建辉王振兴孙丹石广丽张苏苏艾军于淼刘雨萌吴姝逸吉林农业大学园艺学院长春130118

【目的】探究不同光照强度对五味子psii活性的影响。【方法】以两份五味子‘早红’与‘铁岭-0601’资源为试材,对二者叶片进行0、600、1200、1800μmol/(m^(2)·s)光照处理。【结果】强光易导致光合机构受到光损伤。强光胁迫使得五味子... 详细信息

【目的】探究不同光照强度对五味子psii活性的影响。【方法】以两份五味子‘早红’与‘铁岭-0601’资源为试材,对二者叶片进行0、600、1200、1800μmol/(m^(2)·s)光照处理。【结果】强光易导致光合机构受到光损伤。强光胁迫使得五味子叶片psii供体侧与受体侧受到伤害,电子传递受阻,产生大量活性氧(ROS),使丙二醛(MDA)积累量增加,发生膜质过氧化。强光处理下,‘早红’与‘铁岭-0601’均出现K点,二者K点相对可变荧光(V_(K))与J点相对可变荧光(V_(J))随着光照强度的增加而不断升高,1800μmol/(m^(2)·s)光强处理下V_(J)最高;各处理下‘铁岭-0601’V_(J)均高于‘早红’。与0μmol/(m^(2)·s)相比,强光处理下‘早红’与‘铁岭-0601’电子传递效率(φ_(o))、电子传递的量子产额(φ_(Eo))、单位psii叶绿素天线可还原QA反应中心的数量(RC/ABS)、单位面积电子传递的量子产额(ET_(O)/CS_(O))、单位面积捕获的光能(TR_(O)/CS_(O))下降,用于热耗散的量子比率(φ_(Do))、单位面积吸收的光能(ABS/CS_(O))、单位面积的热耗散(DI_(O)/CS_(O))上升。随着光照强度的升高,‘早红’与‘铁岭-0601’的MDA积累量增加,且各处理下‘铁岭-0601’的MDA积累量均高于‘早红’。‘早红’与‘铁岭-0601’叶片的花色苷积累量具有显著差异,前者是后者的3.16倍。【结论】五味子不同种质资源对强光的响应具有差异,‘早红’强光胁迫下psii电子传递体活性强,抵御强光能力更强。

关键词：五味子强光胁迫 psii

Low Root Zone Temperature Exacerbates the Ion Imbalance and Photosynthesis Inhibition and Induces Antioxidant Responses in Tomato Plants Under Salinity

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2014年第1期13卷 89-99页

作者： HE Yong YANG Jing ZHU Biao ZHU Zhu-jun Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province/College of Agricultural and Food Science Zhejiang A&F University

The combined effects of salinity with low root zone temperature （RZT） on plant growth and photosynthesis were studied in tomato （Solanum lycopersicum） plants. The plants were exposed to two different root zone temperatures （28/20℃, 12/8℃, day/night temperature） in combination with two NaC1 levels （0 and 100 mmol L-l）. After 2 wk of treatment, K＋ and Na~ concentration, leaf photosynthetic gas exchange, chlorophyll fluorescence and leaf antioxidant enzyme activities were measured. Salinity significantly decreased plant biomass, net photosynthesis rate, actual quantum yield of photosynthesis and concentration of K＋, but remarkably increased the concentration of Na＋. These effects were more pronounced when the salinity treatments were combined with the treatment of low RZT conditions. Either salinity or low RZT individually did not affect maximal efficiency of psii photochemistry （Fv/Fm）, while a combination of these two stresses decreased Fv/Fm considerably, indicating that the photo-damage occurred under such conditions. Non-photochemical quenching was increased by salt stress in accompany with the enhancement of the de-epoxidation state of the xanthophyll cycle, in contrast, this was not the case with low RZT applied individually. Salinity stress individually increased the activities of SOD, APX, GPOD and GR, and decreased the activities of DHAR. Due to the interactive effects of salinity with low RZT, these five enzyme activities increased sharply in the combined stressed plants. These results indicate that low RZT exacerbates the ion imbalance, psii damage and photosynthesis inhibition in tomato plants under salinity. In response to the oxidative stress under salinity in combination with low RZT, the activities of antioxidant enzymes SOD, APX, GPOD, DHAR and GR were clearly enhanced in tomato plants.

关键词： antioxidant enzyme chlorophyll fluorescence ion concentration low root zone temperature psii salinity