四通道動態(tài)LED陣列近紅外光譜儀
DUAL-KLAS-NIR
同步測量PSII活性（葉綠素熒光）和PSI活性（P700）
PC（質(zhì)體藍素）Fd（鐵氧還蛋白）的氧化還原變化
2016年2月Photosynthesis Research雜志發(fā)表了Schreiber博士團隊的研究文章Deconvolution of ferredoxin, plastocyanin, and P700 transmittance changes in intact leaves with a new type of kinetic LED array spectrophotometer，隆重介紹了DUAL-KLAS-NIR四通道動態(tài)LED陣列近紅外光譜儀。之后2016年4月，2017年3月Schreiber博士團隊再次發(fā)表文章，進一步闡述DUAL-KLAS-NIR的實際應用。
作為PSI的電子供體和電子受體，PC（質(zhì)體藍素）和Fd（鐵氧還蛋白）對PSI的氧化還原起著至關重要的調(diào)控作用。但一直缺乏科學便捷的手段對其運轉狀態(tài)進行檢測。集成以DUALl-PAM-100為標志的第二代PAM的基本功能，采用先進的去卷積技術（一種根據(jù)來源不同對信號進行分離的技術），WALZ公司推出了可以測量PC和Fd氧化還原狀態(tài)的新一代PAM熒光儀—DUAL-KLAS-NIR四通道動態(tài)LED陣列近紅外光譜儀。
DUAL-KLAS-NIR不但集成了Dual-PAM-100的基本功能，可以同時測量PSP和PSI，而且能夠測量4組不同波段（780-820nm，820-870nm，840-965nm，870-965nm）的信號，實現(xiàn)對P700（PSI反應中心）、PC和Fd的氧化還原狀態(tài)分別測量。另外，它還可以測量由540nm和460nm光化光激發(fā)的葉綠素熒光。利用DUAL-KLAS-NIR四通道動態(tài)LED陣列近紅外光譜儀，可以準同步地測量各種不同的信號，不僅在馳豫動力下，還可持續(xù)地在自然穩(wěn)態(tài)下同時獲取各組分的信息。
突出特點
? 可測量活體葉片或懸浮液，對P700、PC和Fd分別進行連續(xù)的實時的去卷積分析。
? 同時測量分別由540nm（整個葉片）和460nm（表層細胞層）波段激發(fā)的兩種葉綠素熒光。
? 通過集成發(fā)光二極管技術，獨創(chuàng)高度緊湊的固態(tài)照明系統(tǒng)，提供635nm，460nm的光化光和740nm波段遠紅光，以及635nm單周轉和多周轉飽和閃光。
? 擁有和DUAL-PAM-100相似的光學部件幾何結構，可與3010-DUAL兼容，結合GFS-3000光合儀，在可控條件（光照，溫度，濕度，CO2濃度）下，同步測量氣體交換和電子傳遞相關的氧化還原。
? 測量光頻率范圍廣（1 - 400 kHz），允許連續(xù)評估Fo，可以在高時間分辨率下記錄快速動態(tài)瞬變（如多相熒光上升動力學或脈沖弛豫動力學）。
主要功能
? 測定質(zhì)體藍素（PC），PS I反應中心（P700）和鐵氧還蛋白（Fd）的氧化還原變化。
? 通過應用創(chuàng)新的分析方法獲得PC，P700和Fd光譜特征。在線監(jiān)測P700，PC和Fd的氧化還原變化，并確定PC / P700和Fd / P700的比值。
? 可以通過綠色或藍色PAM測量光來激發(fā)熒光。綠光比藍光更深入到葉子中。因此，綠色激發(fā)的熒光包括來自更深葉層的信息，因此非常適合與整個葉子的NIR吸收測量進行對比分析。
? 專業(yè)數(shù)據(jù)記錄軟件，入門特別簡單?？墒褂肈UAL-KLAS-NIR軟件的自動測量程序實驗，也可以編輯腳本（Script）或者保存手動測量程序（Trigger），輕松執(zhí)行復雜的測量協(xié)議?？勺远x測量動作用于特殊誘導過程動力學曲線數(shù)據(jù)獲取和分析。
? 兼具慢速動力學曲線（飽和脈沖分析、誘導曲線和光響應曲線）和快速動力學曲線（飽和脈沖動力學曲線、高達30μs分辨率的馳豫動力學曲線）。
DUAL-KLAS-NIR軟件近紅外測量光設置 |
同步測量Fluo, P700, PC, Fd慢速誘導動力學曲線 |
應用領域
光合作用電子傳遞過程各復合體的氧化還原狀態(tài)深入剖析，類囊體膜蛋白組分功能研究。
可廣泛應用于光合合成生物學研究相關的植物學，植物生理學，分子生物學，農(nóng)學，林學的領域。
應用案例
DUAL-KLAS-NIR為光合作用開辟了一個全新的研究領域，實時顯示P700，PC和Fd在活體材料中的氧化還原狀態(tài)，在線解卷積氧化還原信號。完美實現(xiàn)PS I及其供體側和受體側氧化還原動力學的同步測量，從而了解它們圍繞光系統(tǒng)I的復雜相互作用，另外還可以探究PS I周圍的循環(huán)電子傳遞的信息。
在DUAL-KLAS-NIR出現(xiàn)之前，測量光系統(tǒng)I的有效量子產(chǎn)量，P700信號總是會摻雜Fd的貢獻和PC的變量。上圖中圖C顯示了不同光強梯度下甘藍型油菜葉片PSI的有效PSI量子產(chǎn)量Y(I)，PSII的有效量子產(chǎn)量Y(II)和經(jīng)PSI熒光修正后的PSII的有效量子產(chǎn)率Y(II)corr。經(jīng)過修正后，Y(II)corr和Y(I)在低光強下相似（小于500μmol m-2 s-1）。然而，當光強大于500μmol m-2 s-1時，Y(I)明顯高于Y(II)，Y(I)/Y(II)最高可達1.45.
光系統(tǒng)I的有效天線尺寸測量。植物樣品從在黑暗條件轉移到光下時，在PSI附近，首先PC被氧化，開始積累，之后才是P700被氧化。單純的PC信號變化的初始斜率可以用作PS I的有效天線尺寸的度量。
| 右圖是放大后的PC（紅色）和P700（藍色）初始吸光度變化，顯示了他們初始斜率的巨大差異。對于黑暗適應的葉子，轉到光下的短時間內(nèi)，光系統(tǒng)I受體側未活化，F(xiàn)d還原的初始斜率也也說明了這一點。 |  |
DUAL-KLAS-NIR軟件設有一個窗口顯示P700和PC氧化還原狀態(tài)的相對變化。該功能可以用來計算PC和P700之間的表觀平衡常數(shù)。這對研究P700與其供體側的相互關系是非常重要的。 |  |
對暗適應的葉子施加飽和脈沖，測量Fd氧化還原動力學。我們不難發(fā)現(xiàn)，飽和脈沖產(chǎn)生的電子將Fd還原，飽和脈沖之后的黑暗中，F(xiàn)d被緩慢再氧化。之后，PSI的受體側的電子流被激活，再氧化動力學變得更快。在激活PSI的受體側之后，可以通過監(jiān)測脈沖后Fd再氧化的速率來研究Fd的暗滅活。這些動力學變化可以通過指數(shù)擬合程序擬合。圖A給出了Fd再氧化動力學曲線指數(shù)擬合程序擬合的實例，圖B顯示了常春藤葉片不同暗適應時間后的PSI受體側的暗滅活動力學差異。
PC，P700和Fd的最大NIR透射率變化與這些復合物的在樣品中的含量成比例，并且PC，P700和Fd的消光系數(shù)的比率是恒定的。這可以用于探究不同物種或不同生長條件下（例如陽生/陰生，脅迫/非脅迫）樣品的PC / P700和Fd / P700比率，以及PC和Fd庫的相對大小。現(xiàn)已觀察到高PC / P700比率與高電子傳遞速率（ETR）值相關。上圖顯示，在常春藤陽生和陰生葉片中，相對于P700，它們PC和Fd含量有著顯著的不同。
主要測量參數(shù)：
? 葉綠素熒光測量：Fo, Fm, Fm’, F, Fo’, Fv/Fm, Y(II), qP, qL, qN, NPQ, Y(NO), Y(NPQ) , ETR(II)等參數(shù)，以及各種熒光動力學曲線。
? P700測量：必須能夠測量Pm, Pm’, Y(I), ETR(I)， Y(ND)和Y(NA)等參數(shù)，以及各種P700動力學曲線。
? PC測量：PCm, PCm’, PCox, Rel PCox
? Fd測量：Fdm, Fdm’, Fdred, Rel Fdred, Fd/PC
? 實時顯示數(shù)據(jù)采集，可以連續(xù)顯示數(shù)據(jù)采集過程即完整的動力學曲線過程
? 軟件程序：慢速動力學曲線，快速動動力學曲線，曲線擬合
產(chǎn)地：德國WALZ
代表文獻
數(shù)據(jù)來源：光合作用文獻Endnote數(shù)據(jù)庫
原始數(shù)據(jù)來源：Google Scholar
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