Hatier Jean-Hugues B, Gould Kevin S
School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
Department of Botany, University of Otago, PO Box 56, Dunedin, New Zealand.
Funct Plant Biol. 2007 Mar;34(2):130-138. doi: 10.1071/FP06220.
Black-pigmented leaves occur only rarely in nature, possibly because their efficiency of light capture for photosynthesis is low. Using near-isogenic morphs of black- and green-leafed Ophiopogon planiscapus Nakai 'Nigrescens', we tested the possibility that black pigmentation restricts the transmission of PAR within the leaf. We measured chromaticity coordinates of black and green leaf phenotypes, quantified their pigments and optical properties, and followed the transmission profiles of red, blue and green light through lamina tissues. Chroma and lightness values for the black leaves were comparable to those of a black paint standard, and were lower than those for the green phenotype, or for green and anthocyanic leaves of three other species. The adaxial surface of black leaves absorbed 95% incident quanta, and reflected 4% across the entire 400-700 nm waveband. There were no obvious structural differences between black and green leaves. Black coloration correlated with luxuriant concentrations of both chlorophylls and anthocyanins in superficial mesophyll. Profiles of transmission of red and blue light were similar in green and black leaves. In contrast, green light was restricted to uppermost palisade mesophyll layers in black leaves, but was transmitted to more central mesophyll in green leaves.
自然界中黑色叶片极为罕见，这可能是因为它们用于光合作用的光捕获效率较低。我们利用黑叶和绿叶麦冬‘Nigrescens’的近等基因形态，测试了黑色色素沉着限制叶片内光合有效辐射（PAR）传输的可能性。我们测量了黑色和绿色叶片表型的色度坐标，对其色素和光学特性进行了量化，并跟踪了红、蓝和绿光通过叶片组织的传输情况。黑色叶片的色度和亮度值与黑色油漆标准相当，低于绿色表型或其他三个物种的绿色和花青素叶片。黑色叶片的上表面在整个400 - 700纳米波段吸收了95%的入射量子，反射了4%。黑色和绿色叶片之间没有明显的结构差异。黑色与表层叶肉中叶绿素和花青素的丰富浓度相关。红蓝光在绿色和黑色叶片中的传输情况相似。相比之下，绿光在黑色叶片中仅限于最上层的栅栏叶肉层，但在绿色叶片中传输到更靠中心的叶肉。
