Intra-leaf gradients of photoinhibition induced by different color lights: implications for the dual mechanisms of photoinhibition and for the application of conventional chlorophyll fluorometers
Intra-leaf gradients of photoinhibition induced by different color lights: implications for the dual mechanisms of photoinhibition and for the application of conventional chlorophyll fluorometers
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DOI：
10.1111/j.1469-8137.2011.03669.x
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发表时间：
2011-01-01
期刊：
影响因子：
9.4
通讯作者：
Terashima, Ichiro
中科院分区：
文献类型：
--
作者：
Oguchi, Riichi;Douwstra, Peter;Terashima, Ichiro
我们研究了不同颜色的光如何在叶片内引起光抑制的梯度，以试图解决光抑制的主要原因是由叶绿素吸收的光子还是由锰(Mn)吸收的光，分别是过剩能量假说或两步假说。林可霉素处理的叶盘分别受到白色、蓝色、绿色或红光的光抑制。结合微型纤维荧光仪、纤维细化技术和显微操纵器，我们能够测量叶片内的叶绿素荧光信号。光抑制强度由大到小依次为近轴面蓝光、红光和绿光，组织深层为蓝光、绿光和红光，分别与叶绿素和锰的吸收光谱相关。这些结果不能单独用任何一种假说来解释。这些数据强烈地表明，光抑制中存在过剩能量和两步机制，与整个组织的平均值相比，红色或蓝色测量光的荧光仪分别高估或低估了光抑制叶片的F-v/F-m值，即它们分别测量了较深或较浅的叶片组织。
We studied how different color lights cause gradients of photoinhibition within a leaf, to attempt to resolve the controversy of whether photon absorption by chlorophyll or by manganese (Mn) is the primary cause of photoinhibition, as suggested by the excess-energy hypothesis or the two-step hypothesis, respectively.Lincomycin-treated leaf discs were photoinhibited by white, blue, green or red light. Combining a microfiber fluorometer, a fiber-thinning technique and a micromanipulator enabled us to measure the chlorophyll fluorescence signals within a leaf. Photoinhibition gradients were also compared with results from various conventional fluorometers to estimate their depth of signal detection.The severity of photoinhibition was in the descending order of blue, red and green light near the adaxial surface, and in the descending order of blue, green and red light in the deeper tissue, which correlated with the chlorophyll and the Mn absorption spectrums, respectively. These results cannot be explained by either hypothesis alone.These data strongly suggest that both the excess-energy and the two-step mechanisms occur in photoinhibition, and fluorometers with red or blue measuring light give overestimated or underestimated F-v/F-m values of photoinhibited leaves compared with the whole tissue average, respectively; that is, they measured deeper or shallower leaf tissue, respectively.