Multiple origins of crassulacean acid metabolism and the epiphytic habit in the Neotropical family Bromeliaceae
Multiple origins of crassulacean acid metabolism and the epiphytic habit in the Neotropical family Bromeliaceae
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新热带植物凤梨科（Bromeliaceae）骨胶原酸代谢和附生习性的多重起源
DOI：
10.1073/pnas.0400366101
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发表时间：
2004-03-09
影响因子：
11.1
通讯作者：
Smith, JAC
中科院分区：
文献类型：
--
作者：
Crayn, DM;Winter, K;Smith, JAC
凤梨科是新热带区植物适应辐射的一个突出例子，它包含了广泛的陆生和附生生活型，占据了许多不同的生境。凤梨科植物的多样化与几个关键的创新有关，包括蓄水和营养的植物根，吸收性表皮毛，以及被称为景天酸代谢（CAM）的光合作用的节水模式。为了阐明CAM和附生习性的起源，我们进行了系统发育分析的核苷酸序列的51凤梨分类群，通过使用质体位点matK和rps 16内含子，结合碳同位素比值测定的光合作用途径的调查，为1,873种占65%的家庭。严格的共识树上的字符状态优化表明，凤梨科的最后共同祖先是一个陆地的C-3中生植物，可能适应潮湿，暴露，营养不良的栖息地。CAM光合作用和附生习性在该家族中至少进化了三次，最有可能是对晚第三纪地质和气候变化的反应。绝大多数的附生形式现在被发现在两个谱系：在亚科Tillandsioideae，其中C-3光合作用是最极端的附生植物的祖先状态和CAM发展较晚，并在亚科Bromelioideae，其中CAM光合作用先于附生的外观。随后的辐射bromelioid线到干旱的栖息地，导致逆转的C-3光合作用在一些类群，CAM的增益和损失都发生在这个家庭的复杂的进化历史。
The large Neotropical family Bromeliaceae presents an outstanding example of adaptive radiation in plants, containing a wide range of terrestrial and epiphytic life-forms occupying many distinct habitats. Diversification in bromeliads has been linked to several key innovations, including water- and nutrient-impounding phytotelmata, absorptive epidermal trichomes, and the water-conserving mode of photosynthesis known as crassulacean acid metabolism (CAM). To clarify the origins of CAM and the epiphytic habit, we conducted a phylogenetic analysis of nucleotide sequences for 51 bromeliad taxa by using the plastid loci matK and the rps16 intron, combined with a survey of photosynthetic pathway determined by carbon-isotope ratios for 1,873 species representing 65% of the family. Optimization of character-states onto the strict consensus tree indicated that the last common ancestor of Bromeliaceae was a terrestrial C-3 mesophyte, probably adapted to moist, exposed, nutrient-poor habitats. Both CAM photosynthesis and the epiphytic habit evolved a minimum of three times in the family, most likely in response to geological and climatic changes in the late Tertiary. The great majority of epiphytic forms are now found in two lineages: in subfamily Tillandsioideae, in which C-3 photosynthesis was the ancestral state and CAM developed later in the most extreme epiphytes, and in subfamily Bromelioideae, in which CAM photosynthesis predated the appearance of epiphytism. Subsequent radiation of the bromelioid line into less xeric habitats has led to reversion to C-3 photosynthesis in some taxa, showing that both gain and loss of CAM have occurred in the complex evolutionary history of this family.