Light absorption efficiencies of photosynthetic pigments: the dependence on spectral types of central stars
Light absorption efficiencies of photosynthetic pigments: the dependence on spectral types of central stars
复制标题
光合色素的光吸收效率：对中心恒星光谱类型的依赖
DOI：
10.1017/s147355041400072x
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发表时间：
2015
影响因子：
1.7
通讯作者：
Kazuhiro Yabana and Kenji Shiraishi
中科院分区：
文献类型：
--
作者：
Yu Komatsu;Masayuki Umemura;Mitsuo Shoji;Megumi Kayanuma;Kazuhiro Yabana and Kenji Shiraishi
从太阳系外行星的反射光谱中探测生命，光合作用的痕迹是指标之一。然而，目前还不清楚什么样的辐射环境适合光合作用。在地球上的光系统中，光吸收是利用有限的光合色素，如叶绿素（Chls）和细菌叶绿素（BChls）。通过计算高精度量子力学水平的特定分子吸收光谱来评估颜料的光吸收效率。我们使用了F、G、K和m型恒星等真实的恒星辐射光谱来研究效率。我们发现效率随着恒星温度的增加而增加，从M星到F星。光合色素有两种类型的吸收带，Qy和Soret。在像F星这样温度较高的恒星中，色素的Soret区对效率的贡献占主导地位。另一方面，在像M星这样温度较低的恒星中，Qy波段至关重要。因此，Qy和Soret波段的吸收强度和波长的差异是表征光合色素最重要的指标。在光合色素中，Chls在高温恒星中更有效，而BChls在高温恒星中更有效。在4000 Å裂口的前方，bchl的效率比高温恒星中的chl要小。
For detecting life from reflection spectra on extrasolar planets, trace of photosynthesis is one of the indicators. However, it is not yet clear what kind of radiation environments is acceptable for photosynthesis. Light absorption in photosystems on the Earth occurs using limited photosynthetic pigments such as chlorophylls (Chls) and bacteriochlorophylls (BChls). Efficiencies of light absorption for the pigments were evaluated by calculating the specific molecular absorption spectra at the high accuracy-quantum mechanical level. We used realistic stellar radiation spectra such as F, G, K and M-type stars to investigate the efficiencies. We found that the efficiencies are increased with the temperature of stars, from M to F star. Photosynthetic pigments have two types of absorption bands, the Qy and Soret. In higher temperature stars like F star, contributions from the Soret region of the pigments are dominant for the efficiency. On the other hand, in lower temperature stars like M stars, the Qy band is crucial. Therefore, differences on the absorption intensity and the wavelength between the Qy and Soret band are the most important to characterize the photosynthetic pigments. Among photosynthetic pigments, Chls tend to be efficient in higher temperature stars, while BChls are efficient for M stars. Blueward of the 4000 Å break, the efficiencies of BChls are smaller than Chls in the higher temperature stars.