• 【类胡萝卜素的电荷转移可以抑制植物天线复合物中的叶绿素激发。】 复制标题 收藏 收藏
    DOI:10.1038/s41467-020-14488-6 复制DOI
    作者列表:Cupellini L,Calvani D,Jacquemin D,Mennucci B
    BACKGROUND & AIMS: :The photosynthetic apparatus of higher plants can dissipate excess excitation energy during high light exposure, by deactivating excited chlorophylls through a mechanism called nonphotochemical quenching (NPQ). However, the precise molecular details of quenching and the mechanism regulating the quenching level are still not completely understood. Focusing on the major light-harvesting complex LHCII of Photosystem II, we show that a charge transfer state involving Lutein can efficiently quench chlorophyll excitation, and reduce the excitation lifetime of LHCII to the levels measured in the deeply quenched LHCII aggregates. Through a combination of molecular dynamics simulations, multiscale quantum chemical calculations, and kinetic modeling, we demonstrate that the quenching level can be finely tuned by the protein, by regulating the energy of the charge transfer state. Our results suggest that a limited conformational rearrangement of the protein scaffold could act as a molecular switch to activate or deactivate the quenching mechanism.
    背景与目标: : 高等植物的光合装置可以通过一种称为非光化学猝灭 (NPQ) 的机制使激发的叶绿素失活,从而在高光照射期间消散多余的激发能量。然而,淬火的精确分子细节和调节淬火水平的机理仍不完全清楚。着眼于光系统II的主要集光复合物LHCII,我们表明,涉及叶黄素的电荷转移状态可以有效地抑制叶绿素激发,并将LHCII的激发寿命降低到深度淬灭的LHCII聚集体中测得的水平。通过分子动力学模拟,多尺度量子化学计算和动力学建模的组合,我们证明了通过调节电荷转移状态的能量,蛋白质可以微调猝灭水平。我们的结果表明,蛋白质支架的有限构象重排可以充当分子开关,以激活或停用猝灭机制。
  • 【适应不同温度条件的树种的叶绿素荧光参数与光化学反射指数之间的关系。】 复制标题 收藏 收藏
    DOI:10.1071/FP05156 复制DOI
    作者列表:Weng JH,Chen YN,Liao TS
    BACKGROUND & AIMS: :Chlorophyll fluorescence parameters and spectral reflectance at leaf level were measured at both predawn and noon, under different temperatures and natural light conditions from autumn to winter. Predawn Fv / Fm of both mango (Mangifera indica L.), a tropical fruit tree, and Podocarpus nagi Zoll. et Moritz., a subtropical conifer, decreased with decreasing temperature, with the former to a greater extent than the latter. Yet, predawn Fv / Fm of Taiwan alder (Alnus formosana Makino), a broadleaf tree widely distributed from the lowlands to 3000 m above sea level in Taiwan, was less influenced by temperature. Nevertheless, taking all three species into consideration, predawn Fv / Fm showed a strong correlation with predawn photochemical reflectance index [(PRIp), PRI = (R531 - R570) / (R531 + R570), where R = reflectance]. For the data obtained at noon, ΔF / Fm' showed a significant but weak correlation with PRI (PRIn). However, stronger correlation between ΔF / Fm' and ΔPRI (PRIp - PRIn) was found. In addition, while a non-significant or weak correlation between non-photochemical quenching (NPQ) and PRIn was observed in species sensitive to low temperature, their NPQ was significantly correlated with ΔPRI. We conclude that PRIp can serve as an indicator of the seasonal variation of potential PSII efficiency; and ΔPRI reflects the actual photodissipation as well as actual PSII efficiency during illumination. For the three species in this study, the PRI provides a more consistent measure of the variation in predawn fluorescence values than for steady-state values measured under normal seasonally varying daylight illumination.
    背景与目标: : 在秋季至冬季的不同温度和自然光条件下,在黎明前和中午测量了叶绿素荧光参数和叶片水平的光谱反射率。热带果树芒果 (Mangifera indica L.) 和亚热带针叶树罗汉松 (Podocarpus nagi Zoll. et Moritz。) 的黎明前fv  /fm fm随温度降低而降低,前者比后者更大。然而,台湾al木 (Alnus formosana Makino) 的黎明前fv  / Fm是一种广泛分布于台湾低地至海拔3000  m的阔叶树,受温度的影响较小。然而,考虑到这三个物种,黎明前fv  / Fm与黎明前光化学反射率指数 [(PRIp),PRI = (R531  -  R570) / (R531   +   R570),其中R = 反射率] 具有很强的相关性。对于中午获得的数据,Δ f  /  Fm' 与PRI (PRIn) 表现出显着但弱的相关性。然而,发现 Δ f  /  Fm' 和 Δ pri (PRIp - PRIn) 之间的相关性更强。此外,尽管在对低温敏感的物种中观察到非光化学猝灭 (NPQ) 与PRIn之间的相关性不显着或弱,但它们的NPQ与 Δ pri显着相关。我们得出的结论是,PRIp可以作为潜在PSII效率季节性变化的指标; Δ pri反映了照明过程中的实际光耗散以及实际PSII效率。对于本研究中的三个物种,与在正常季节性变化的日光照明下测得的稳态值相比,PRI提供了对黎明前荧光值变化的更一致的度量。
  • 【在高强度激发光下测得的多相叶绿素a荧光上升。】 复制标题 收藏 收藏
    DOI:10.1071/FP05095 复制DOI
    作者列表:Lazár D
    BACKGROUND & AIMS: :Chlorophyll a fluorescence rise caused by illumination of photosynthetic samples by high intensity of exciting light, the O-J-I-P (O-I1-I2-P) transient, is reviewed here. First, basic information about chlorophyll a fluorescence is given, followed by a description of instrumental set-ups, nomenclature of the transient, and samples used for the measurements. The review mainly focuses on the explanation of particular steps of the transient based on experimental and theoretical results, published since a last review on chlorophyll a fluorescence induction [Lazár D (1999) Biochimica et Biophysica Acta 1412, 1-28]. In addition to 'old' concepts (e.g. changes in redox states of electron acceptors of photosystem II (PSII), effect of the donor side of PSII, fluorescence quenching by oxidised plastoquinone pool), 'new' approaches (e.g. electric voltage across thylakoid membranes, electron transport through the inactive branch in PSII, recombinations between PSII electron acceptors and donors, electron transport reactions after PSII, light gradient within the sample) are reviewed. The K-step, usually detected after a high-temperature stress, and other steps appearing in the transient (the H and G steps) are also discussed. Finally, some applications of the transient are also mentioned.
    背景与目标: : 叶绿素a荧光升高是由高强度的激发光 (o-j-i-P (O-I1-I2-P) 瞬态) 照射光合作用样品引起的。首先,给出有关叶绿素a荧光的基本信息,然后描述仪器设置,瞬态术语以及用于测量的样品。该评论主要侧重于基于实验和理论结果的瞬态的特定步骤的解释,该实验和理论结果自上次对叶绿素a荧光诱导 [laz á r D (1999) Biochimica et Biophysica Acta 1412,1-28] 以来发表。除了 “旧” 概念 (例如光系统II (PSII) 的电子受体的氧化还原状态的变化,PSII的供体侧的影响,氧化的质体醌池的荧光猝灭),“新” 方法 (例如跨类囊体膜的电压,通过PSII中的非活性分支的电子传输,PSII电子受体和供体之间的重组,PSII后的电子传输反应,样品中的光梯度) 进行了综述。还讨论了通常在高温应力后检测到的K步以及瞬态中出现的其他步骤 (H和G步)。最后,还提到了瞬态的一些应用。
  • 【通过GROWSCREEN FLUORO同时对叶片生长和叶绿素荧光进行表型分析,可以检测拟南芥和其他莲座丛植物的胁迫耐受性。】 复制标题 收藏 收藏
    DOI:10.1071/FP09095 复制DOI
    作者列表:Jansen M,Gilmer F,Biskup B,Nagel KA,Rascher U,Fischbach A,Briem S,Dreissen G,Tittmann S,Braun S,De Jaeger I,Metzlaff M,Schurr U,Scharr H,Walter A
    BACKGROUND & AIMS: :Stress caused by environmental factors evokes dynamic changes in plant phenotypes. In this study, we deciphered simultaneously the reaction of plant growth and chlorophyll fluorescence related parameters using a novel approach which combines existing imaging technologies (GROWSCREEN FLUORO). Three different abiotic stress situations were investigated demonstrating the benefit of this approach to distinguish between effects related to (1) growth, (2) chlorophyll-fluorescence, or (3) both of these aspects of the phenotype. In a drought stress experiment with more than 500 plants, poly(ADP-ribose) polymerase (PARP) deficient lines of Arabidopsis thaliana (L.) Heynh showed increased relative growth rates (RGR) compared with C24 wild-type plants. In chilling stress, growth of PARP and C24 lines decreased rapidly, followed by a decrease in Fv/Fm. Here, PARP-plants showed a more pronounced decrease of Fv/Fm than C24, which can be interpreted as a more efficient strategy for survival in mild chilling stress. Finally, the reaction of Nicotiana tabacum L. to altered spectral composition of the intercepted light was monitored as an example of a moderate stress situation that affects chlorophyll-fluorescence related, but not growth-related parameters. The examples investigated in this study show the capacity for improved plant phenotyping based on an automated and simultaneous evaluation of growth and photosynthesis at high throughput.
    背景与目标: : 环境因素引起的胁迫引起植物表型的动态变化。在这项研究中,我们使用一种结合了现有成像技术 (GROWSCREEN FLUORO) 的新颖方法,同时破译了植物生长和叶绿素荧光相关参数的反应。研究了三种不同的非生物胁迫情况,证明了这种方法有助于区分与 (1) 生长,(2) 叶绿素荧光或 (3) 表型这两个方面有关的影响。在对500多种植物的干旱胁迫实验中,拟南芥 (L.) 的聚 (ADP-核糖) 聚合酶 (PARP) 缺陷系与C24野生型植物相比,Heynh的相对生长率 (RGR) 增加。在低温胁迫下,PARP和C24品系的生长迅速下降,随后Fv/Fm下降。在这里,PARP植物显示出比C24更明显的Fv/Fm降低,这可以解释为在轻度低温胁迫下生存的更有效策略。最后,监测了Nicotiana tabacum L.对截获光的光谱组成改变的反应,作为影响叶绿素荧光相关但不影响生长相关参数的中等胁迫情况的一个例子。本研究中研究的实例表明,基于对高通量的生长和光合作用的自动同时评估,可以改善植物表型。
  • 【丙二醛中的捕光叶绿素c样色素。】 复制标题 收藏 收藏
    DOI:10.1073/pnas.91.2.679 复制DOI
    作者列表:Larkum AW,Scaramuzzi C,Cox GC,Hiller RG,Turner AG
    BACKGROUND & AIMS: :A chlorophyll c-like pigment, similar to magnesium-3,8-divinyl pheoporphyrin a5 monomethyl ester, has been isolated from Prochloron sp. obtained from five species of didemnid ascidians from the Great Barrier Reef, Australia, and from Palau, Micronesia. The pigment represents 4-15% of the total chlorophyll content and is shown to function in a light-harvesting pigment protein complex of Prochloron. The observation that all of the major chlorophylls (a+b+c) function in a light-harvesting role in Prochloron and possibly in other prochlorophytes is discussed in terms of the phylogeny of the prochlorophytes.
    背景与目标: : 已从Prochloron sp。中分离出一种叶绿素c样色素,类似于3,8-二乙烯基卟啉镁a5单甲酯。从澳大利亚大堡礁和密克罗尼西亚帕劳的五种didemnid海鞘中获得。该色素占总叶绿素含量的4-15%,并且显示在丙氯酮的光捕获色素蛋白复合物中起作用。根据前叶绿素的系统发育,讨论了所有主要叶绿素 (a b c) 在丙二醛以及可能在其他前叶绿素中起着捕光作用的观察结果。
  • 【高粱叶绿素性状的遗传。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Karper RE,Conner AB
    BACKGROUND & AIMS: -2
    背景与目标: -2
  • 【在扫描隧道显微镜操纵单个叶绿素-a分子中实现四步分子开关。】 复制标题 收藏 收藏
    DOI:10.1073/pnas.0603643103 复制DOI
    作者列表:Iancu V,Hla SW
    BACKGROUND & AIMS: :Single chlorophyll-a molecules, a vital resource for the sustenance of life on Earth, have been investigated by using scanning tunneling microscope manipulation and spectroscopy on a gold substrate at 4.6 K. Chlorophyll-a binds on Au(111) via its porphyrin unit while the phytyl-chain is elevated from the surface by the support of four CH(3) groups. By injecting tunneling electrons from the scanning tunneling microscope tip, we are able to bend the phytyl-chain, which enables the switching of four molecular conformations in a controlled manner. Statistical analyses and structural calculations reveal that all reversible switching mechanisms are initiated by a single tunneling-electron energy-transfer process, which induces bond rotation within the phytyl-chain.
    背景与目标: : 通过在4.6 K的金基板上使用扫描隧道显微镜操纵和光谱学研究了单个叶绿素-a分子,这是维持地球生命的重要资源。叶绿素a通过其卟啉单元在Au(111) 上结合,而植物链通过四个CH(3) 基团的支持从表面升高。通过从扫描隧道显微镜尖端注入隧道电子,我们能够弯曲phytyl链,从而能够以受控方式切换四个分子构象。统计分析和结构计算表明,所有可逆的切换机制都是由单个隧穿电子能量转移过程启动的,该过程会引起植物链内的键旋转。
  • 【植物细胞中的动作电位降低了叶绿素荧光非光化学能量依赖性猝灭的光需求。】 复制标题 收藏 收藏
    DOI:10.1016/j.bbabio.2007.01.004 复制DOI
    作者列表:Krupenina NA,Bulychev AA
    BACKGROUND & AIMS: :This study deals with effects of membrane excitation on photosynthesis and cell protection against excessive light, manifested in non-photochemical quenching (NPQ). In Chara corallina cells, NPQ and pericellular pH displayed coordinated spatial patterns along the length of the cell. The NPQ values were lower in H(+)-extruding cell regions (external pH approximately 6.5) than in high pH regions (pH approximately 9.5). Generation of an action potential by applying a pulse of electric current caused NPQ to increase within 30-60 s. This effect, manifested as a long-lived drop of maximum chlorophyll fluorescence (F(m)'), occurred at lower photosynthetic flux densities (PFD) in the alkaline as compared to acidic cell regions. The light response curve of NPQ shifted, after generation of an action potential, towards lower PFD. The release of NPQ by nigericin and the rapid reversal of action potential-triggered NPQ in darkness indicate its relation to thylakoid DeltapH. Generation of an action potential shortly after darkening converted the chloroplasts into a latent state with the F(m) identical to that of unexcited cells. This state transformed to the quenched state after turning on weak light that was insufficient for NPQ prior to membrane excitation of the cells. The ionophore, A23187, shifted NPQ plots similarly to the action potential effect, consistent with a likely role of a rise in the cytosolic Ca(2+) level in the action potential-induced quenching. The results suggest that a rapid electric signal, across the plasma membrane, might exert long-lived effects on photosynthesis and chlorophyll fluorescence through ion flux-mediated pathways.
    背景与目标: : 本研究涉及膜激发对光合作用和细胞对过度光的保护的影响,表现为非光化学猝灭 (NPQ)。在Chara corallina细胞中,NPQ和细胞周pH沿细胞长度显示出协调的空间模式。在H(+) 挤出细胞区域 (外部pH约6.5) 中的NPQ值低于在高pH区域 (pH约9.5) 中的NPQ值。通过施加电流脉冲产生动作电位,导致NPQ在30-60 s内增加。与酸性细胞区域相比,这种效应表现为最大叶绿素荧光 (F(m)') 的长寿命下降,发生在碱性较低的光合通量密度 (PFD) 下。产生动作电位后,NPQ的光响应曲线向较低的PFD移动。nigericin释放NPQ以及在黑暗中动作电位触发的NPQ的快速逆转表明其与类囊体DeltapH的关系。变暗后不久产生动作电位将叶绿体转化为潜伏状态,其F(m) 与未激发的细胞相同。在打开弱光后,该状态转变为淬灭状态,在细胞膜激发之前,该弱光不足以用于NPQ。离子载体A23187与动作电位效应类似地移动了NPQ图,这与在动作电位诱导的猝灭中胞质Ca(2) 水平升高的可能作用一致。结果表明,跨质膜的快速电信号可能会通过离子通量介导的途径对光合作用和叶绿素荧光产生长期影响。
  • 【具有改变的CO2补偿点的突变体对狗草的高通量叶绿素荧光筛选。】 复制标题 收藏 收藏
    DOI:10.1071/FP17322 复制DOI
    作者列表:Coe RA,Chatterjee J,Acebron K,Dionora J,Mogul R,Lin H,Yin X,Bandyopadhyay A,Sirault XRR,Furbank RT,Quick WP
    BACKGROUND & AIMS: :To assist with efforts to engineer a C4 photosynthetic pathway into rice, forward-genetic approaches are being used to identify the genes modulating key C4 traits. Currently, a major challenge is how to screen for a variety of different traits in a high-throughput manner. Here we describe a method for identifying C4 mutant plants with increased CO2 compensation points. This is used as a signature for decreased photosynthetic efficiency associated with a loss of C4 function. By exposing plants to a CO2 concentration close to the CO2 compensation point of a wild-type plant, individuals can be identified from measurements of chlorophyll a fluorescence. We use this method to screen a mutant population of the C4 monocot Setaria viridis (L.)P.Beauv. generated using N-nitroso-N-methylurea (NMU). Mutants were identified at a frequency of 1 per 157 lines screened. Forty-six candidate lines were identified and one line with a heritable homozygous phenotype selected for further characterisation. The CO2 compensation point of this mutant was increased to a value similar to that of C3 rice. Photosynthesis and growth was significantly reduced under ambient conditions. These data indicate that the screen was capable of identifying mutants with decreased photosynthetic efficiency. Characterisation and next-generation sequencing of all the mutants identified in this screen may lead to the discovery of novel genes underpinning C4 photosynthesis. These can be used to engineer a C4 photosynthetic pathway into rice.
    背景与目标: : 为了协助将C4光合作用途径设计成水稻,正使用正向遗传方法来识别调节C4关键性状的基因。当前,一个主要挑战是如何以高通量的方式筛选各种不同的特征。在这里,我们描述了一种识别具有增加的CO2补偿点的C4突变植物的方法。这被用作与C4功能丧失相关的光合作用效率降低的标志。通过将植物暴露于接近野生型植物的CO2补偿点的CO2浓度,可以从叶绿素a荧光的测量中识别出个体。我们使用此方法筛选了使用N-亚硝基-N-甲基脲 (NMU) 产生的C4单子叶狗血虫 (L.)P.Beauv。的突变群体。以每157筛选的品系1的频率鉴定突变体。鉴定了46个候选品系,并选择了1个具有可遗传纯合表型的品系以进行进一步表征。该突变体的CO2补偿点增加到与C3水稻相似的值。在环境条件下,光合作用和生长显着降低。这些数据表明,该筛选能够鉴定光合效率降低的突变体。在此筛选中鉴定的所有突变体的表征和下一代测序可能会导致发现支撑C4光合作用的新基因。这些可用于将C4光合作用途径改造到水稻中。
  • 【冬绿草本植物Ajuga reptans L中叶片叶绿素-蛋白质复合物的季节性变化。】 复制标题 收藏 收藏
    DOI:10.1071/FP17199 复制DOI
    作者列表:Dymova O,Khristin M,Miszalski Z,Kornas A,Strzalka K,Golovko T
    BACKGROUND & AIMS: :The chlorophyll and carotenoid content, and the spectra of low-temperature fluorescence of the leaves, chloroplasts and isolated pigment-protein complexes in the perennial herbaceous wintergreen plant Ajuga reptans L. (bugle) in different seasons of the year were studied. During winter, these plants downregulate photosynthesis and the PSA is reorganised, including the loss of chlorophyll, possible reductions in the number of functional reaction centres of PSII, and changes in aggregation of the thylakoid protein complexes. We also observed a restructuring of the PSI-PSII megacomplex and the PSII-light-harvesting complex II supercomplex in leaves covered by snow. After snowmelt, the monomeric form of the chl a/b pigment-protein complex associated with PSII (LHCII) and the free pigments were also detected. We expect that snow cover provides favourable conditions for keeping photosynthetic machinery ready for photosynthesis in spring just after snowmelt. During winter, the role of the zeaxanthin-dependent protective mechanism, which is responsible for the dissipation of excess absorbed light energy, is likely to increase.
    背景与目标: : 多年生草本冬绿植物Ajuga reptans L中的叶绿素和类胡萝卜素含量,以及叶片,叶绿体和分离的色素-蛋白质复合物的低温荧光光谱。(军号) 在一年中的不同季节进行了研究。在冬季,这些植物下调了光合作用,PSA被重组,包括叶绿素的损失,PSII功能反应中心数量的可能减少以及类囊体蛋白复合物聚集的变化。我们还观察到被雪覆盖的叶子中PSI-PSII巨复合体和PSII-采光复合体II超复合体的重组。融雪后,还检测到与PSII (LHCII) 相关的chl a/b色素-蛋白复合物的单体形式和游离色素。我们希望积雪为在融雪后的春季保持光合作用机械的准备提供有利条件。在冬季,玉米黄质依赖的保护机制的作用可能会增加,该机制负责消耗过多的吸收光能。
  • 【从不同地理位置采样的葡萄叶片中叶绿素和多酚水平的比较定量。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-020-63407-8 复制DOI
    作者列表:Martín-Tornero E,de Jorge Páscoa RNM,Espinosa-Mansilla A,Martín-Merás ID,Lopes JA
    BACKGROUND & AIMS: :Near infrared spectroscopy (NIRS) and mid-infrared spectroscopy (MIRS) in combination with chemometric analysis were applied to discriminate the geographical origin of grapevine leaves belonging to the variety "Touriga Nacional" during different vegetative stages. Leaves were collected from plants of two different wine regions in Portugal (Dão and Douro) over the grapes maturation period. A sampling plan was designed in order to obtain the most variability within the vineyards taking into account variables such as: solar exposition, land inclination, altitude and soil properties, essentially. Principal component analysis (PCA) was used to extract relevant information from the spectral data and presented visible cluster trends. Results, both with NIRS and MIRS, demonstrate that it is possible to discriminate between the two geographical origins with an outstanding accuracy. Spectral patterns of grapevine leaves show significant differences during grape maturation period, with a special emphasis between the months of June and September. Additionally, the quantification of total chlorophyll and total polyphenol content from leaves spectra was attempted by both techniques. For this purpose, partial least squares (PLS) regression was employed. PLS models based on NIRS and MIRS, both demonstrate a statistically significant correlation for the total chlorophyll (R2P = 0.92 and R2P = 0.76, respectively). However, the PLS model for the total polyphenols, may only be considered as a screening method, because significant prediction errors, independently of resourcing on NIRS, MIRS or both techniques simultaneously, were obtained.
    背景与目标: : 近红外光谱 (NIRS) 和中红外光谱 (MIRS) 与化学计量分析相结合,用于区分不同营养阶段属于 “Touriga Nacional” 品种的葡萄叶的地理来源。在葡萄成熟期,从葡萄牙两个不同葡萄酒产区 (d ã o和Douro) 的植物中收集叶子。设计了一个采样计划,以便在葡萄园内获得最大的可变性,并考虑了诸如以下变量: 太阳暴露,土地倾斜度,海拔和土壤特性。主成分分析 (PCA) 用于从光谱数据中提取相关信息,并呈现可见的聚类趋势。NIRS和MIRS的结果都表明,有可能以出色的准确性区分这两个地理起源。葡萄叶片的光谱模式在葡萄成熟期显示出显着差异,尤其是在6月月份和9月月份之间。此外,两种技术都尝试从叶片光谱中定量总叶绿素和总多酚含量。为此,采用偏最小二乘 (PLS) 回归。基于NIRS和MIRS的PLS模型均显示出总叶绿素的统计学显着相关性 (分别为R2P   =   0.92和R2P   =   0.76)。但是,总多酚的PLS模型只能被认为是一种筛选方法,因为获得了明显的预测误差,而与同时使用NIRS,MIRS或两种技术的资源无关。
  • 【叶片或藻类细胞叶绿素热致发光的陷阱、人工制品和悬而未决的问题。】 复制标题 收藏 收藏
    DOI:10.1007/s11120-013-9859-5 复制DOI
    作者列表:Ducruet JM
    BACKGROUND & AIMS: :Thermoluminescence of intact photosynthetic organisms, leaves or algal cells, raises specific problems. The constitutive S2/3Q B (-) B bands constitute major probes of the state of photosystem II in vivo. The presence of a dark-stable acidic lumen causes a temperature downshift of B bands, specially the S3 B band, providing a lumen pH indicator. This is accompanied by a broadening of the S3 B band that becomes an envelope of elementary B bands. The occasional AT, Q and C bands are briefly examined in an in vivo context. It is emphasized that freezing below the nucleation temperature is not necessary for physiological studies, but a source of artefacts, hence should be avoided. In intact photosynthetic structures, a dark-electron transfer from stroma reductants to the quinonic acceptors of photosystem II via the cyclic/chlororespiratory pathways, strongly stimulated by moderate warming, gives rise to the afterglow (AG) luminescence emission that reflects chloroplast energy status. The decomposition of complex TL signals into elementary bands is necessary to determine the maximum temperature T m and the area of each of them. A comparison of TL signals after 1 flash and 2 flashes prevents from confusing the three main bands observed in vivo, i.e. the S2 and S3 B bands and the AG band. Finally, the thermoluminescence bands arising sometimes above 50 °C are mentioned. The basic principles of (thermo)luminescence established on isolated thylakoids should not be applied directly without a careful examination of in vivo conditions.
    背景与目标: : 完整的光合生物,叶子或藻类细胞的热发光引起了特定的问题。组成性S2/3Q B (-) B带构成体内光系统II状态的主要探针。暗稳定的酸性腔的存在会导致B带 (特别是S3 B带) 的温度下降,从而提供腔pH指示剂。这伴随着S3 B波段的加宽,成为基本B波段的包络。在体内环境中简要检查了偶尔出现的AT,Q和C带。需要强调的是,对于生理研究而言,冻结在成核温度以下不是必需的,而是伪影的来源,因此应避免。在完整的光合结构中,通过循环/氯呼吸途径从基质还原剂到光系统II的奎尼离子受体的暗电子转移,受到中等温度的强烈刺激,会产生反映叶绿体能量状态的余辉 (AG) 发光发射。必须将复杂的TL信号分解为基本频带,以确定最高温度T m和每个频带的面积。1次闪光和2次闪光后的TL信号的比较防止混淆体内观察到的三个主要带,即S2和S3 B带和AG带。最后,提到了有时在50 °C以上出现的热致发光带。在分离的类囊体上建立的 (热) 发光的基本原理不应在没有仔细检查体内条件的情况下直接应用。
  • 【NAP通过与拟南芥中的DELLAs相互作用,参与GA介导的叶绿素降解和叶片衰老。】 复制标题 收藏 收藏
    DOI:10.1007/s00299-019-02474-2 复制DOI
    作者列表:Lei W,Li Y,Yao X,Qiao K,Wei L,Liu B,Zhang D,Lin H
    BACKGROUND & AIMS: KEY MESSAGE:RGA/GAI and NAP interacted with each other, and NAP was involved in GA signaling as a role of regulating age-dependent and dark-induced leaf senescence in Arabidopsis. Leaf senescence is a significant biological process which is beneficial for plant growth, development, and generation alternation in Arabidopsis. Recent researches have shown gibberellins (GAs) could accelerate leaf senescence. Nevertheless, the GA signaling involved in leaf senescence process remains elusive. Here, we reported a new potential regulation mechanism of GA-mediated chlorophyll degradation and leaf senescence. In this study, we confirmed that NAP positively regulated age-dependent and dark-induced leaf senescence and NAP knockout mutant nap was hyposensitive to GA3 (an active form of GA) treatment. DELLA family proteins with highly conserved structural domain function as master growth repressors that integrated GA signaling and leaf senescence. We validated RGA and GAI could interact with NAP in vitro and in vivo, and subsequently impaired the transcriptional activities of NAP to induce SAG113 and AAO3 expression in nap protoplasts. Taken together, we suggest that NAP is a novel component of the regulatory network that modulates the progress of leaf senescence in GA signaling.
    背景与目标: 关键信息: RGA/GAI和NAP相互作用,NAP作为调节拟南芥年龄依赖性和黑暗诱导的叶片衰老的作用参与GA信号传导。叶片衰老是一个重要的生物学过程,有利于拟南芥植物的生长,发育和世代交替。最近的研究表明,赤霉素 (GAs) 可以加速叶片衰老。尽管如此,叶片衰老过程中涉及的GA信号仍然难以捉摸。在这里,我们报道了GA介导的叶绿素降解和叶片衰老的新的潜在调控机制。在这项研究中,我们证实了NAP正向调节年龄依赖性和黑暗诱导的叶片衰老,并且NAP敲除突变体nap对GA3 (GA的一种活性形式) 处理不敏感。具有高度保守的结构域功能的DELLA家族蛋白作为整合GA信号传导和叶片衰老的主要生长阻遏物。我们验证了RGA和GAI可以在体外和体内与NAP相互作用,随后损害了NAP的转录活性,从而诱导了nap原生质体中SAG113和AAO3的表达。总之,我们建议NAP是调节GA信号中叶片衰老进程的调节网络的新组成部分。
  • 【OsDET1的突变增加了水稻的叶绿素含量。】 复制标题 收藏 收藏
    DOI:10.1016/j.plantsci.2013.06.003 复制DOI
    作者列表:Huang J,Qin F,Zang G,Kang Z,Zou H,Hu F,Yue C,Li X,Wang G
    BACKGROUND & AIMS: :As an important agronomic trait, the chlorophyll (Chl) content is closely related to photosynthesis in plants. A rice mutant Gc (Oryza sativa indica) was characterized previously by its enhanced Chl content (Chl b and total Chl) and exaggerated photosynthetic rate. Here, we describe the enhanced Chl content was caused by a mutation in the rice homolog of the DE-ETIOLATED1 (DET1) known to be involved in light transduction and morphogenesis in Arabidopsis and tomato. Sequence analysis revealed that the Gc mutant carried two fragment-insertions and a fragment-deletion upstream of the start codon of OsDET1, which led to enhance mRNA levels of OsDET1. Besides, the Gc mutant harbored a single T-to-C base transversion in the seventh exon of OsDET1, which resulted in leucine(328) to serine(328) localized in the highly conserved region. Genetic complementation demonstrated that OsDET1 mutation conferred the enhanced Chl content in the Gc mutant leaf. OsDET1 was richly expressed in green tissues, and its expression seems to be under circadian control. OsDET1-GFP fusion protein in onion epidermal cells showed that OsDET1 localized to the nucleus. These results indicated that OsDET1 mutation in Gc mutant increases Chl content in rice, which might be fundamental for enhanced photoresponsiveness.
    背景与目标: 作为重要的农艺性状,叶绿素 (Chl) 含量与植物的光合作用密切相关。水稻突变体Gc (Oryza sativa indica) 以前的特征是其Chl含量 (Chl b和总Chl) 和光合速率过高。在这里,我们描述了Chl含量的增加是由已知与拟南芥和番茄的光转导和形态发生有关的DE-ETIOLATED1 (DET1) 的水稻同源物突变引起的。序列分析表明,Gc突变体在OsDET1的起始密码子上游携带两个片段插入和一个片段缺失,从而提高了OsDET1的mRNA水平。此外,Gc突变体在OsDET1的第七外显子中具有单个T-C碱基转位,这导致亮氨酸 (328) 到丝氨酸 (328) 位于高度保守的区域。遗传互补表明,OsDET1突变使Gc突变体叶片中的Chl含量增加。OsDET1在绿色组织中表达丰富,其表达似乎处于昼夜节律控制之下。洋葱表皮细胞中的OsDET1-GFP融合蛋白显示OsDET1定位于细胞核。这些结果表明,Gc突变体中的OsDET1突变会增加水稻中的Chl含量,这可能是增强光响应能力的基础。
  • 【通过OJIP叶绿素a荧光测量探测的挪威云杉 (Picea abies L. Karst。) 营养芽和针中的PSII光化学。】 复制标题 收藏 收藏
    DOI:10.1556/ABiol.63.2012.2.5 复制DOI
    作者列表:Katanić Z,Atić L,Ferhatović D,Cesar V,Lepeduš H
    BACKGROUND & AIMS: :Vegetative buds represent developmental stage of Norway spruce (Picea abies L. Karst.) needles where chloroplast biogenesis and photosynthetic activity begin. We used the analyses of polyphasic chlorophyll a fluorescence rise (OJIP) to compare photosystem II (PSII) functioning in vegetative buds and fully photosynthetically active mature current-year needles. Considerably decreased performance index (PIABS) in vegetative buds compared to needles pointed to their low photosynthetic efficiency. Maximum quantum yield of PSII (Fv/Fm) in buds was slightly decreased but above limited value for functionality indicating that primary photochemistry of PSII is not holdback of vegetative buds photosynthetic activity. The most significant difference observed between investigated developmental stages was accumulation of reduced primary quinine acceptor of PSII (QA-) in vegetative buds, as a result of its limited re-oxidation by passing electrons to secondary quinone acceptor, QB. We suggest that reduced electron transfer from QA- to QB could be the major limiting factor of photosynthesis in vegetative buds.
    背景与目标: : 营养芽代表挪威云杉 (Picea abies L. Karst。) 针的发育阶段,叶绿体生物发生和光合活性开始。我们使用多相叶绿素a荧光上升 (OJIP) 的分析来比较光系统II (PSII) 在营养芽和完全光合作用的成熟当年针中的功能。与针叶相比,营养芽的性能指数 (PIABS) 大大降低,这表明它们的光合作用效率低。芽中PSII的最大量子产量 (Fv/Fm) 略有降低,但高于功能的极限值,这表明PSII的主要光化学作用并不抑制营养芽的光合活性。在研究的发育阶段之间观察到的最显着差异是营养芽中PSII (QA-) 的初级奎宁受体的减少积累,这是由于其通过将电子传递给次级醌受体QB而受到限制的再氧化。我们建议减少从QA到QB的电子转移可能是营养芽光合作用的主要限制因素。

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