Secondary phloem diversity and evolution in Bignonieae (Bignoniaceae)

• DOI: 10.1093/aob/mcv106
• Publication Date: 2015-08-26T11:51:43Z
• Authors: Marcelo R. Pace; Suzana Alcantara; Lúcia G. Lohmann; Veronica Angyalossy
• Keywords: Sieve tube element; Tribe

Background and Aims Phloem evolution has been explored in the literature across very broad scales, either for vascular plants as a whole or major plant groups, such monocotyledons former dicotyledons. However, it never examined way that would elucidate evolutionary shifts leading to diversification of phloem single lineages. Therefore, present study explores detail patterns tribe Bignonieae (Bignoniaceae). This group represents particularly good model studies since is known have conspicuous diverse phloem. Methods A total 19 characters were coded 56 species from all 21 genera currently recognized Bignonieae, accounting wedge growth anatomical cell diversity encountered was by reconstructing ancestral character states using maximum-likelihood assumptions with time-calibrated molecular phylogeny group. Directionality effect phylogenetic transformations current variation quantitative traits correlations selected discrete also tested under approach. Key Results Individual features are quite tribe, but generally conserved within smaller clades. Contrasting found when comparing certain lineages having marked background fibres where other cells embedded, tangentially arranged sieve tubes sieve-tubecentric parenchyma. In contrast, exhibited scarcely fibrous phloem, regularly stratified tube elements radial diffuse arrangement, We signals directional fibre abundance number areas, which increased ‘Fridericia allies extended clade’ decreased ‘Multiples four clade’, resulting no signal directionality considered. indication axial parenchyma, clades entire tribe. Positive correlation between element length both plate type presence storied structure. Correlated several traits, type, parenchyma ray lignification companion cells. Conclusions The secondary extremely diverse, sister exhibiting distinct anatomies derived contrasting abundance. Fibre diversified morphology, type. results challenge long-standing hypotheses regarding general trends morphological demonstrate need expand anatomy at narrow taxonomic scale one, families orders.