BACKGROUND & AIMS: :The phototransformation pathways of protochlorophyllide forms were studied in 8-14-day-old leaves of dark-germinated wheat (Triticum aestivum L.) using white, 632.8 nm He-Ne laser and 654 nm laser diode light. The photon flux density (PFD) values (0.75-360 μmol photons m(-2) s(-1)), the illumination periods (20 ms-10 s) and the temperature of the leaves (between -60 °C and room temperature) were varied. The 77 K fluorescence spectra of partially phototransformed leaves showed gradual accumulation or even the dominance of the 675 nm emitting chlorophyllide or chlorophyll form at room temperature with 632.8 nm of PFD less than 200 μmol photons m(-2) s(-1) or with 654 nm of low PFD (7.5 μmol photons m(-2) s(-1)) up to 1 s. Longer wavelength (685 or 690 nm) emitting chlorophyllide forms appeared at illuminations under -25 °C with both laser lights or at room temperature when the PFD values were higher or the illumination period was longer than above. We concluded that the formation of the 675 nm emitting chlorophyllide form does not indicate the direct photoactivity of the 633 nm emitting protochlorophyllide form; it can derive from 644 and 657 nm forms via instantaneous disaggregation of the newly-produced chlorophyllide complexes. The disaggregation is strongly influenced by the molecular environment and the localization of the complex.

背景与目标： : 使用白色，632.8 nm He-Ne激光和654 nm激光二极管光，在8-14日龄的深色发芽小麦 (Triticum aestivum L.) 的叶片中研究了原叶绿素形式的光转化途径。光子通量密度 (PFD) 值 (0.75-360 μ mol光子m(-2) s(-1))，光照周期 (20 ms-10 s) 和叶片温度 (-60 °C和室温之间) 变化。部分光转化的叶片的77 k荧光光谱显示，在室温下，632.8 nm的PFD小于200 μ mol光子m(-2) s(-1) 或654 nm的低PFD (7.5 μ mol光子m(-2) s(-1)) 最多1 s。当PFD值较高或照射周期长于以上时，在-25 °C下用两种激光照射下或在室温下，发射叶绿素形式出现更长的波长 (685或690 nm)。我们得出的结论是，发射675 nm的叶绿素形式的形成并不表明发射633 nm的原叶绿素形式的直接光活性; 它可以通过新产生的叶绿素复合物的瞬时分解从644和657 nm形式衍生而来。分解受到分子环境和复合物定位的强烈影响。

BACKGROUND & AIMS: :In the photosynthetic membrane, there is a particular aggregated state for the chlorophyll a (Chl a) molecules with a specific arrangement responsible for the high efficiency of energy conversion. Chl a monolayers, transferred onto solid substrates, are systems that potentially can mimic the packing of the in vivo system. The association of Chl a in the monolayer results in the formation of dimers with an average size of 3.00 +/- 0.15 nm. Considering the organization of the dimers, we assume that P680 is a dimer with the (anti) parallel transition moments of the constituent. The Chl a macrocycles most likely are tilted to each other by 30 degrees with respect to the membrane plane.

背景与目标： : 在光合膜中，叶绿素a (Chl a) 分子具有特定的聚集状态，具有特定的排列方式，负责能量转换的高效率。转移到固体底物上的Chl a单层是可能模仿体内系统堆积的系统。单层中Chl a的缔合导致形成平均尺寸为3.00 +/- 0.15 nm的二聚体。考虑到二聚体的组织，我们假设P680是具有成分的 (反) 平行跃迁矩的二聚体。Chl a大环最有可能相对于膜平面彼此倾斜30度。

BACKGROUND & AIMS: :We studied the charge recombination characteristics of Photosystem II (PSII) redox components in whole cells of the chlorophyll (Chl) d-dominated cyanobacterium, Acaryochloris marina, by flash-induced chlorophyll fluorescence and thermoluminescence measurements. Flash-induced chlorophyll fluorescence decay was retarded in the mus and ms time ranges and accelerated in the s time range in Acaryochloris marina relative to that in the Chl a-containing cyanobacterium, Synechocystis PCC 6803. In the presence of 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, which blocks the Q(B) site, the relaxation of fluorescence decay arising from S(2)Q(A)(-) recombination was somewhat faster in Acaryochloris marina than in Synechocystis PCC 6803. Thermoluminescence intensity of the so called B band, arising from the recombination of the S(2)Q(B)(-) charge separated state, was enhanced significantly (2.5 fold) on the basis of equal amounts of PSII in Acaryochloris marina as compared with Synechocystis 6803. Our data show that the energetics of charge recombination is modified in Acaryochloris marina leading to a approximately 15 meV decrease of the free energy gap between the Q(A) and Q(B) acceptors. In addition, the total free energy gap between the ground state and the excited state of the reaction center chlorophyll is at least approximately 25-30 meV smaller in Acaryochloris marina, suggesting that the primary donor species cannot consist entirely of Chl a in Acaryochloris marina, and there is a contribution from Chl d as well.

背景与目标： : 我们通过闪光诱导的叶绿素荧光和热释光测量研究了叶绿素 (Chl) d为主的蓝细菌Acaryochloris marina的整个细胞中光系统II (PSII) 氧化还原成分的电荷重组特性。相对于含Chl a的蓝细菌，Synechocystis PCC 6803，闪蒸诱导的叶绿素荧光衰减在mus和ms时间范围内被延迟，而在s时间范围内被加速。在阻断Q(B) 位点的3-(3,4-二氯苯基)-1,1-二甲基脲的存在下，由S(2)Q(A)(-) 重组引起的荧光衰减的弛豫在Acaryochloris marina中比在Synechocystis PCC 6803中略快。由于S(2)Q(B)(-) 电荷分离状态的重组而产生的所谓B带的热致发光强度在与6803的集胞藻相比，基于等量的Acaryochloris marina中的PSII显著增强 (2.5倍)。我们的数据表明，在Acaryochloris marina中电荷重组的能量得到了改变，导致Q (a) 和Q(B) 受体之间的自由能隙降低了约15 meV。此外，在Acaryochloris marina中，反应中心叶绿素的基态和激发态之间的总自由能隙至少小约25-30 meV，这表明主要供体物种不能完全由Acaryochloris marina中的Chl a组成，chl d也做出了贡献。

BACKGROUND & AIMS: :Differential kinetic absorption spectra were measured during actinic illumination of photosystem II reaction centres and core complexes in the presence of electron acceptors silicomolybdate and ferricyanide. The spectra of samples with ferricyanide differ from those with both ferricyanide and silicomolybdate. Near-infrared spectra show temporary beta-carotene and peripheral chlorophyll oxidation during room temperature actinic illumination. Peripheral chlorophyll is photooxidized even after decay of beta-carotene oxidation activity and significant reduction of beta-carotene content in both reaction centres and photosystem II core complexes. Besides, new carotenoid cation is observed after about 1 s of actinic illumination in the reaction centres when silicomolybdate is present. Similar result was observed in PSII core complexes. HPLC analyses of illuminated reaction centres reveal several novel carotenoids, whereas no new carotenoid species were observed in HPLC of illuminated core complexes. Our data support the proposal that pigments of inner antenna are a sink of cations originating in the photosystem II reaction centre.

背景与目标： : 在存在电子受体硅钼酸盐和铁氰化物的情况下，在光化照射光系统II反应中心和核心配合物期间测量了微分动力学吸收光谱。具有铁氰化物的样品的光谱与具有铁氰化物和硅钼酸盐的样品的光谱不同。近红外光谱显示室温光化照明过程中暂时的 β-胡萝卜素和外围叶绿素氧化。即使在反应中心和光系统II核心复合物中 β-胡萝卜素氧化活性下降和 β-胡萝卜素含量显着降低之后，外周叶绿素也被光氧化。此外，当硅钼酸盐存在时，在反应中心进行约1 s的光化照射后，观察到新的类胡萝卜素阳离子。在PSII核心复合物中观察到类似的结果。对照明反应中心的HPLC分析揭示了几种新型的类胡萝卜素，而在照明核心复合物的HPLC中未观察到新的类胡萝卜素种类。我们的数据支持以下建议: 内部天线的颜料是源自光系统II反应中心的阳离子汇。

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。

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。

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。

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。

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。

BACKGROUND & AIMS: -2

背景与目标： -2

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。

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。

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。

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。

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。