0000000001317249
AUTHOR
Katharina Bohley
C 3 –C 4 intermediates may be of hybrid origin – a reminder
Summary The currently favoured model of the evolution of C4 photosynthesis relies heavily on the interpretation of the broad phenotypic range of naturally growing C3–C4 intermediates as proxies for evolutionary intermediate steps. On the other hand, C3–C4 intermediates had earlier been interpreted as hybrids or hybrid derivates. By first comparing experimentally generated with naturally growing C3–C4 intermediates, and second summarising either direct or circumstantial evidence for hybridisation in lineages comprising C3, C4 and C3–C4 intermediates, we conclude that a possible hybrid origin of C3–C4 intermediates deserves careful examination. While we acknowledge that the current model of C…
Phylogeny of Sesuvioideae (Aizoaceae) – Biogeography, leaf anatomy and the evolution of C4 photosynthesis
Abstract Sesuvioideae (Aizoaceae) form a small subfamily of drought-tolerant plants exhibiting leaf succulence, halophytic ecology, and the C4 photosynthetic pathway. Sesuvioideae are sister to the species-rich subfamilies Ruschioideae, Mesembryanthemoideae and Aizooideae that contain many CAM lineages. This close relationship of CAM and C4 taxa identifies the Sesuvioideae as an important clade to address hypotheses of photosynthetic pathway evolution. This study presents a molecular phylogeny of Sesuvioideae based on five markers (atpB-rbcL spacer, rps16 intron, trnL-trnF spacer, petB-petD spacer, ITS) and 51 accessions representing all genera and 37 species. We determined carbon isotope d…
C4-like photosynthesis and the effects of leaf senescence on C4-like physiology in Sesuvium sesuvioides (Aizoaceae).
Sesuvium sesuvioides represents a young C4 lineage with C4-like metabolism: CO2 compensation points range between C4 and C3–C4 intermediate values, and Rubisco was detected in bundle sheath and mesophyll.
A Revision of Sesuvium (Aizoaceae, Sesuvioideae)
Sesuvium and Cypselea are closely related succulent genera within the Sesuvioideae (Aizoaceae). Since Cypselea is nested in Sesuvium in molecular studies and both genera share traits separating them from other members of the subfamily, we propose to include Cypselea in Sesuvium. Sesuvium (incl. Cypselea) comprises 14 species and is distributed worldwide with centres of diversity in southern Africa and North and Central America. Sesuvium comprises erect to procumbent herbs with opposite leaves that often bear conspicuous sheath-like lateral appendages on the petioles (pseudostipules). These and the many-seeded capsules are diagnostic traits, separating Sesuvium from the closely related gener…
A note on leaf venation and the circumscription of Tephroseris (Asteraceae–Senecioneae)
Molecular phylogenetic results had shown that Tephroseris, a genus differentiated from its closest relatives by its pinnately veined leaves, also contains species with palmate leaf venation. This had led to the conclusion that leaf venation is a homoplasious character in the lineage containing Tephroseris. We here take a closer look at leaf venation in Tephroseris and other species of Asteraceae–Senecioneae. We found that leaf venation in Tephroseris is distinct from leaf venation in Jacobaea vulgaris and Senecio vulgaris, which both have pinnately veined leaves as typical for most species of their respective genera, and that description of the leaves of Tephroseris as pinnately veined is i…
Data from: A revision of Sesuvium (Aizoaceae, Sesuvioideae)
Sesuvium and Cypselea are closely related succulent genera within the Sesuvioideae (Aizoaceae). Since Cypselea is nested in Sesuvium in molecular studies and both genera share traits separating them from other members of the subfamily, we propose to include Cypselea in Sesuvium. Sesuvium (incl. Cypselea) comprises 14 species and is distributed worldwide with centres of diversity in southern Africa and North and Central America. Sesuvium comprises erect to procumbent herbs with opposite leaves that often bear conspicuous sheath-like lateral appendages on the petioles (pseudostipules). These and the many-seeded capsules are diagnostic traits, separating Sesuvium from the closely related gener…