Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia.
LI-COR Inc., Lincoln, NE 68504, USA.
Plant Cell Physiol. 2017 Oct 1;58(10):1652-1660. doi: 10.1093/pcp/pcx103.
Chl fluorescence has been used widely to calculate photosynthetic electron transport rates. Portable photosynthesis instruments allow for combined measurements of gas exchange and Chl fluorescence. We analyzed the influence of spectral quality of actinic light on Chl fluorescence and the calculated electron transport rate, and compared this with photosynthetic rates measured by gas exchange in the absence of photorespiration. In blue actinic light, the electron transport rate calculated from Chl fluorescence overestimated the true rate by nearly a factor of two, whereas there was closer agreement under red light. This was consistent with the prediction made with a multilayer leaf model using profiles of light absorption and photosynthetic capacity. Caution is needed when interpreting combined measurements of Chl fluorescence and gas exchange, such as the calculation of CO2 partial pressure in leaf chloroplasts.
叶绿素荧光已被广泛用于计算光合作用电子传递速率。便携式光合作用仪器允许对气体交换和叶绿素荧光进行联合测量。我们分析了光质对叶绿素荧光和计算出的电子传递速率的影响，并将其与无光合作用下通过气体交换测量的光合速率进行了比较。在蓝光照射下，由叶绿素荧光计算得出的电子传递速率高估了真实速率近两倍，而在红光下则更接近真实速率。这与使用光吸收和光合作用能力分布剖面的多层叶片模型的预测一致。在解释叶绿素荧光和气体交换的联合测量结果时，如叶片叶绿体中 CO2 分压的计算，需要谨慎。
