The CAM lineages of planet Earth

作者：Ian S. Gilman, J. Andrew C. Smith, Joseph A. M. Holtum, Rowan F. Sage, Katia Silvera, Klaus Winter, Erika J. Edwards · 发表于：Annals of Botany · 年份：2023 · DOI：10.1093/aob/mcad135 · 被引用次数：71 · 研究领域：Plant Diversity and Evolution、Plant and Biological Electrophysiology Studies、Plant Gene Expression Analysis

BACKGROUND AND SCOPE: The growth of experimental studies of crassulacean acid metabolism (CAM) in diverse plant clades, coupled with recent advances in molecular systematics, presents an opportunity to re-assess the phylogenetic distribution and diversity of species capable of CAM. It has been more than two decades since the last comprehensive lists of CAM taxa were published, and an updated survey of the occurrence and distribution of CAM taxa is needed to facilitate and guide future CAM research. We aimed to survey the phylogenetic distribution of these taxa, their diverse morphology, physiology and ecology, and the likely number of evolutionary origins of CAM based on currently known lineages. RESULTS AND CONCLUSIONS: We found direct evidence (in the form of experimental or field observations of gas exchange, day-night fluctuations in organic acids, carbon isotope ratios and enzymatic activity) for CAM in 370 genera of vascular plants, representing 38 families. Further assumptions about the frequency of CAM species in CAM clades and the distribution of CAM in the Cactaceae and Crassulaceae bring the currently estimated number of CAM-capable species to nearly 7 % of all vascular plants. The phylogenetic distribution of these taxa suggests a minimum of 66 independent origins of CAM in vascular plants, possibly with dozens more. To achieve further insight into CAM origins, there is a need for more extensive and systematic surveys of previously unstudied lineages, particularly...