Confocal microscopy of thylakoid autofluorescence in relation to origin of grana and phylogeny in the green algae
Confocal microscopy of thylakoid autofluorescence in relation to origin of grana and phylogeny in the green algae
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DOI：
10.1071/pp99076
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发表时间：
1999-01-01
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影响因子：
--
通讯作者：
Schwartz, OM
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文献类型：
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作者：
Gunning, BES;Schwartz, OM
共聚焦显微镜被用来检查在选定的绿色藻类的叶绿体中的叶绿素荧光的异质性，在光的证据表明，该技术揭示了光系统II（PSII）的分布。观察到三个水平的复杂性：（1）均匀荧光（松藻属）或在电子显微镜下已知的属中明亮和不太明亮的荧光的过渡区，具有不规则的类囊体附着区（例如衣原体-其中Bertos和Gibbs（J. Phycol.，34，1009，1998）已经发现光系统I（PSI）和PSII（Ulothrix，Stigeoclonium，Draparnaldia）的分离不存在;（2）在更有组织的类囊体堆积的分类群中，在不太明亮的均匀背景上的1-2 μ m荧光斑的图案（但不是更高的植物）是通过电子显微镜观察到的。（石莼属，鞘藻属）;（3）在相对无荧光的背景中有0.5-2 μ m的离散荧光斑点，与高等植物的基粒非常相似（刚毛藻纲、双星藻目、鞘毛藻目、丽藻属）。这些国家的进一步调查可能会照亮高等植物类囊体系统的进化，其中PSII分离到基粒，并可能提供有关基粒的适应性优势的线索。在大多数分类群中发现了假定的PSII荧光与类蛋白核的关联，尽管仅在一种情况下看到了反式类蛋白核类囊体的荧光。无论蛋白核周围是否有淀粉鞘，这种结合都是普遍存在的，并且在从水绵中分离出的蛋白核中是持久的。我们推测，这种荧光可能代表PSII的一个子集，其与类囊体碳酸酐酶一起发挥功能，以向类核芯中的Rubisco提供局部高浓度的CO2，如Raven所预测的（Plant，Cell and Environment，20，147，1997）。
Confocal microscopy was used to examine heterogeneity of chlorophyll fluorescence in chloroplasts of selected green algae, in the light of evidence that the technique reveals the distribution of photosystem II (PSII). Three levels of complexity were seen: (1) uniform fluorescence (Codium) or intergrading zones of bright and less bright fluorescence in genera known from electron microscopy to have irregular areas of thylakoid appression (e.g. Chlamydomonas - in which Bertos and Gibbs (J. Phycol., 34, 1009, 1998) have found absence of segregation of photosystem I (PSI) and PSII, Ulothrix, Stigeoclonium, Draparnaldia); (2) a pattern of 1-2 mu m patches of fluorescence on a less bright uniform background, in taxa where more organized thylakoid stacking (but not grana sensu higher plants) is seen by electron microscopy (Ulva, Oedogonium); and (3) Discrete 0.5-2 mu m spots of fluorescence in a relatively fluorescence-free background, closely resembling higher plant grana (Cladophorophyceae, Zygnematales, Coleochaete, Nitella). Further investigation of these states may illuminate the evolution of higher plant thylakoid systems, where PSII is segregated into grana, and may provide clues concerning the adaptive advantages of grana. Association of putative PSII fluorescence with pyrenoids was found in most taxa, although fluorescence of trans-pyrenoid thylakoids was seen in one case only. The association prevails whether or not there is a starch sheath around the pyrenoids, and is persistent in pyrenoids isolated from Spirogyra. We speculate that this fluorescence may represent a subset of PSII that functions with thylakoid carbonic anhydrase to provide locally high concentrations of CO2 to the Rubisco in the pyrenoid core, as predicted by Raven (Plant, Cell and Environment, 20, 147, 1997).