Molecular phylogenetics of suborder Cactineae (Caryophyllales), including insights into photosynthetic diversification and historical biogeography

Abstract

Although the C(3) pathway is inferred as the ancestral state in Cactineae, some CAM activity has been reported in the literature in almost every family of the suborder, leaving open the possibility that CAM may have one origin in the group. Incongruence among loci could be due to internal short branches, which possibly represent rapid radiations in response to increasing aridity in the Miocene.

A broader model for C 4 photosynthesis evolution in plants inferred from the goosefoot family (Chenopodiaceae s.s.)

“…These diverse origins led to a range of fundamentally different C 4 anatomies in different lineages and might also be responsible for the fact that, in contrast to C 4 grasses, C 4 chenopods can be found in extremely dry environments. Indeed, a model that describes C 4 evolution in chenopods might better explain C 4 origins in exclusively arid lineages such as Mollugo cerviana and Mollugo fragilis [60], Chamaesyce [61] or Portulaca [62] than might one appropriate for grasses. In general, these results illustrate the critical importance of ancestral states and past environmental conditions in generating the high diversity of C 4 syndromes observed across monocots and dicots.…”

Phylogenetic Relationships Between and within Phacelia Sections Whitlavia and Gymnobythus (Boraginaceae)

“…The rise of C 4 photosynthesis in monocots is estimated at 32.0-25.0 mya for Chloridoideae (Christin et al, 2008) and 10-20 mya for Cyperaceae (Besnard et al, 2009). Portulaca is the oldest known lineage of C 4 eudicots, having diverged 6 30 mya (Ocampo & Columbus, 2010;Christin et al, 2011).…”

Flora do Ceará, Brasil: Cactaceae

“…A circunscrição de Cactaceae dentro das Caryophyllales sempre foi bem aceita entre os diferentes autores, embora sua relação com as outras famílias permaneça incerta (Ocampo & Columbus 2010). Destaca-se que tanto os dados morfológicos como genéticos suportam que a família seja monofilética (Ocampo & Columbus 2010;Hernández-Hernández et al 2011).…”