Sage Rowan F
Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada.
New Phytol. 2004 Feb;161(2):341-370. doi: 10.1111/j.1469-8137.2004.00974.x.
C photosynthesis is a series of anatomical and biochemical modifications that concentrate CO around the carboxylating enzyme Rubisco, thereby increasing photosynthetic efficiency in conditions promoting high rates of photorespiration. The C pathway independently evolved over 45 times in 19 families of angiosperms, and thus represents one of the most convergent of evolutionary phenomena. Most origins of C photosynthesis occurred in the dicots, with at least 30 lineages. C photosynthesis first arose in grasses, probably during the Oligocene epoch (24-35 million yr ago). The earliest C dicots are likely members of the Chenopodiaceae dating back 15-21 million yr; however, most C dicot lineages are estimated to have appeared relatively recently, perhaps less than 5 million yr ago. C photosynthesis in the dicots originated in arid regions of low latitude, implicating combined effects of heat, drought and/or salinity as important conditions promoting C evolution. Low atmospheric CO is a significant contributing factor, because it is required for high rates of photorespiration. Consistently, the appearance of C plants in the evolutionary record coincides with periods of increasing global aridification and declining atmospheric CO . Gene duplication followed by neo- and nonfunctionalization are the leading mechanisms for creating C genomes, with selection for carbon conservation traits under conditions promoting high photorespiration being the ultimate factor behind the origin of C photosynthesis. Contents Summary 341 I. Introduction 342 II. What is C photosynthesis? 343 III. Why did C photosynthesis evolve? 347 IV. Evolutionary lineages of C photosynthesis 348 V. Where did C photosynthesis evolve? 350 VI. How did C photosynthesis evolve? 352 VII. Molecular evolution of C photosynthesis 361 VIII. When did C photosynthesis evolve 362 IX. The rise of C photosynthesis in relation to climate and CO 363 X. Final thoughts: the future evolution of C photosynthesis 365 Acknowledgements 365 References 365.
C4光合作用是一系列解剖学和生物化学修饰，其将二氧化碳浓缩在羧化酶核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco）周围，从而在促进高光呼吸速率的条件下提高光合效率。C4途径在被子植物的19个科中独立进化了45次以上，因此代表了最趋同的进化现象之一。C4光合作用的大多数起源发生在双子叶植物中，至少有30个谱系。C4光合作用最早出现在禾本科植物中，可能是在渐新世时期（2400-3500万年前）。最早的C4双子叶植物可能是藜科植物的成员，可追溯到1500-2100万年前；然而，大多数C4双子叶植物谱系估计是相对较近才出现的，可能不到500万年前。双子叶植物中的C4光合作用起源于低纬度干旱地区，这意味着热量、干旱和/或盐度的综合影响是促进C4进化的重要条件。低大气二氧化碳是一个重要因素，因为它是高光呼吸速率所必需的。一致的是，进化记录中C4植物的出现与全球干旱加剧和大气二氧化碳下降的时期相吻合。基因复制后接着新功能化和非功能化是产生C4基因组的主要机制，在促进高光呼吸的条件下对碳守恒性状的选择是C4光合作用起源背后的最终因素。内容摘要341 一、引言342 二、什么是C4光合作用？343 三、为什么C4光合作用会进化？347 四、C4光合作用的进化谱系348 五、C4光合作用在哪里进化？350 六、C4光合作用是如何进化的？352 七、C4光合作用的分子进化361 八、C4光合作用何时进化？362 九、C4光合作用的兴起与气候和二氧化碳的关系363 十、最后的思考：C4光合作用的未来进化365 致谢365 参考文献365
