四通道动态LED阵列近红外光谱仪
DUAL-KLAS-NIR
同步测量PSII活性（叶绿素荧光）和PSI活性（P700）
PC（质体蓝素）Fd（铁氧还蛋白）的氧化还原变化
2016年2月Photosynthesis Research杂志发表了Schreiber博士团队的研究文章Deconvolution of ferredoxin, plastocyanin, and P700 transmittance changes in intact leaves with a new type of kinetic LED array spectrophotometer，隆重介绍了DUAL-KLAS-NIR四通道动态LED阵列近红外光谱仪。之后2016年4月，2017年3月Schreiber博士团队再次发表文章，进一步阐述DUAL-KLAS-NIR的实际应用。
作为PSI的电子供体和电子受体，PC（质体蓝素）和Fd（铁氧还蛋白）对PSI的氧化还原起着至关重要的调控作用。但一直缺乏科学便捷的手段对其运转状态进行检测。集成以DUALl-PAM-100为标志的第二代PAM的基本功能，采用先进的去卷积技术（一种根据来源不同对信号进行分离的技术），WALZ公司推出了可以测量PC和Fd氧化还原状态的新一代PAM荧光仪—DUAL-KLAS-NIR四通道动态LED阵列近红外光谱仪。
DUAL-KLAS-NIR不但集成了Dual-PAM-100的基本功能，可以同时测量PSP和PSI，而且能够测量4组不同波段（780-820nm，820-870nm，840-965nm，870-965nm）的信号，实现对P700（PSI反应中心）、PC和Fd的氧化还原状态分别测量。另外，它还可以测量由540nm和460nm光化光激发的叶绿素荧光。利用DUAL-KLAS-NIR四通道动态LED阵列近红外光谱仪，可以准同步地测量各种不同的信号，不仅在驰豫动力下，还可持续地在自然稳态下同时获取各组分的信息。
突出特点
Ø 可测量活体叶片或悬浮液，对P700、PC和Fd分别进行连续的实时的去卷积分析。
Ø 同时测量分别由540nm（整个叶片）和460nm（表层细胞层）波段激发的两种叶绿素荧光。
Ø 通过集成发光二极管技术，独创高度紧凑的固态照明系统，提供635nm，460nm的光化光和740nm波段远红光，以及635nm单周转和多周转饱和闪光。
Ø 拥有和DUAL-PAM-100相似的光学部件几何结构，可与3010-DUAL兼容，结合GFS-3000光合仪，在可控条件（光照，温度，湿度，CO2浓度）下，同步测量气体交换和电子传递相关的氧化还原。
Ø 测量光频率范围广（1 - 400 kHz），允许连续评估Fo，可以在高时间分辨率下记录快速动态瞬变（如多相荧光上升动力学或脉冲弛豫动力学）。
主要功能
Ø 测定质体蓝素（PC），PS I反应中心（P700）和铁氧还蛋白（Fd）的氧化还原变化。
Ø 通过应用创新的分析方法获得PC，P700和Fd光谱特征。在线监测P700，PC和Fd的氧化还原变化，并确定PC / P700和Fd / P700的比值。
Ø 可以通过绿色或蓝色PAM测量光来激发荧光。绿光比蓝光更深入到叶子中。因此，绿色激发的荧光包括来自更深叶层的信息，因此非常适合与整个叶子的NIR吸收测量进行对比分析。
Ø 专业数据记录软件，入门特别简单。可使用DUAL-KLAS-NIR软件的自动测量程序实验，也可以编辑脚本（Script）或者保存手动测量程序（Trigger），轻松执行复杂的测量协议。可自定义测量动作用于特殊诱导过程动力学曲线数据获取和分析。
Ø 兼具慢速动力学曲线（饱和脉冲分析、诱导曲线和光响应曲线）和快速动力学曲线（饱和脉冲动力学曲线、高达30µs分辨率的驰豫动力学曲线）。
DUAL-KLAS-NIR软件近红外测量光设置 |
同步测量Fluo, P700, PC, Fd慢速诱导动力学曲线 |
应用领域
光合作用电子传递过程各复合体的氧化还原状态深入剖析，类囊体膜蛋白组分功能研究。
可广泛应用于光合合成生物学研究相关的植物学，植物生理学，分子生物学，农学，林学的领域。
应用案例
DUAL-KLAS-NIR为光合作用开辟了一个全新的研究领域，实时显示P700，PC和Fd在活体材料中的氧化还原状态，在线解卷积氧化还原信号。完美实现PS I及其供体侧和受体侧氧化还原动力学的同步测量，从而了解它们围绕光系统I的复杂相互作用，另外还可以探究PS I周围的循环电子传递的信息。
在DUAL-KLAS-NIR出现之前，测量光系统I的有效量子产量，P700信号总是会掺杂Fd的贡献和PC的变量。上图中图C显示了不同光强梯度下甘蓝型油菜叶片PSI的有效PSI量子产量Y(I)，PSII的有效量子产量Y(II)和经PSI荧光修正后的PSII的有效量子产率Y(II)corr。经过修正后，Y(II)corr和Y(I)在低光强下相似（小于500μmol m-2 s-1）。然而，当光强大于500μmol m-2 s-1时，Y(I)明显高于Y(II)，Y(I)/Y(II)最高可达1.45.
光系统I的有效天线尺寸测量。植物样品从在黑暗条件转移到光下时，在PSI附近，首先PC被氧化，开始积累，之后才是P700被氧化。单纯的PC信号变化的初始斜率可以用作PS I的有效天线尺寸的度量。
| 右图是放大后的PC（红色）和P700（蓝色）初始吸光度变化，显示了他们初始斜率的巨大差异。对于黑暗适应的叶子，转到光下的短时间内，光系统I受体侧未活化，Fd还原的初始斜率也也说明了这一点。 |  |
DUAL-KLAS-NIR软件设有一个窗口显示P700和PC氧化还原状态的相对变化。该功能可以用来计算PC和P700之间的表观平衡常数。这对研究P700与其供体侧的相互关系是非常重要的。 |  |
对暗适应的叶子施加饱和脉冲，测量Fd氧化还原动力学。我们不难发现，饱和脉冲产生的电子将Fd还原，饱和脉冲之后的黑暗中，Fd被缓慢再氧化。之后，PSI的受体侧的电子流被激活，再氧化动力学变得更快。在激活PSI的受体侧之后，可以通过监测脉冲后Fd再氧化的速率来研究Fd的暗灭活。这些动力学变化可以通过指数拟合程序拟合。图A给出了Fd再氧化动力学曲线指数拟合程序拟合的实例，图B显示了常春藤叶片不同暗适应时间后的PSI受体侧的暗灭活动力学差异。
PC，P700和Fd的最大NIR透射率变化与这些复合物的在样品中的含量成比例，并且PC，P700和Fd的消光系数的比率是恒定的。这可以用于探究不同物种或不同生长条件下（例如阳生/阴生，胁迫/非胁迫）样品的PC / P700和Fd / P700比率，以及PC和Fd库的相对大小。现已观察到高PC / P700比率与高电子传递速率（ETR）值相关。上图显示，在常春藤阳生和阴生叶片中，相对于P700，它们PC和Fd含量有着显著的不同。
主要测量参数：
Ø 叶绿素荧光测量：Fo, Fm, Fm’, F, Fo’, Fv/Fm, Y(II), qP, qL, qN, NPQ, Y(NO), Y(NPQ) , ETR(II)等参数，以及各种荧光动力学曲线。
Ø P700测量：必须能够测量Pm, Pm’, Y(I), ETR(I)， Y(ND)和Y(NA)等参数，以及各种P700动力学曲线。
Ø PC测量：PCm, PCm’, PCox, Rel PCox
Ø Fd测量：Fdm, Fdm’, Fdred, Rel Fdred, Fd/PC
Ø 实时显示数据采集，可以连续显示数据采集过程即完整的动力学曲线过程
Ø 软件程序：慢速动力学曲线，快速动动力学曲线，曲线拟合
产地：德国WALZ
代表文献
数据来源：光合作用文献Endnote数据库
原始数据来源：Google Scholar
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