Ontogeny, structure and occurrence of interxylary cambia in Malpighiaceae

Author(s)

Pace, Marcelo R. ^{[1, 2]} ; Acevedo-Rodriguez, Pedro ^[1] ; Amorim, Andre M. ^{[3, 4]} ; Angyalossy, Veronica ^[2]

Affiliation

^[1] Smithsonian Inst, Dept Bot, Natl Museum Nat Hist, Constitut Ave & 10th St NW, MRC 166, Washington, DC 20560 - USA

^[2] Univ Sao Paulo, Inst Biociencias, Dept Bot, Rua Matao 277, Cidade Univ, BR-0550809 Sao Paulo, SP - Brazil

^[3] Univ Estadual Santa Cruz, Dept Ciencias Biol, Km 25, BR-45662900 Ilheus, BA - Brazil

^[4] CEPEC, Herbario Ctr Pesquisa Cacau, Km 22, Rodovia Ilheus, BR-45600970 Itabuna, BA - Brazil

• Document type: Journal article
• Source: FLORA; v. 241, p. 46-60, APR 2018.
• Web of Science Citations: 4

Abstract

Deviations in the regular pattern of secondary growth have occurred multiple times over the history of woody plants and these have been treated under the term cambial variant. Here we present a type of cambial variant that has been studied in the 19th century, but that has never been named or had its ontogeny studied in detail. This cambial variant generates a vascular cylinder with a conspicuous crenate pattern and it is found in two lianescent lineages of Malpighiaceae; Stigmaphyllon and a clade informally called the Banisteriopsis nummifera group. Twenty species of Stigmaphyllon and two species of the Banisteriopsis nummifera group were sampled from naturally growing population to investigate ontogenic history starting from shoot apex to the thickest portion of stem by using traditional anatomical methods All species in these two clades have a regular cambium that produces bands of non-lignified axial parenchyma in the xylem by the onset of secondary growth. These xylem parenchyma cells, after a period of secondary growth, acquire meristematic activity and give rise to new, variant cambia referred here as `interxylary cambia'. These new cambia give rise to new vascular tissues within the secondary xylem. In Stigmaphyllon the variant cambia give rise to a large quantity of variant phloem, and not much variant xylem, while in the members of the Banisteriospsis nummifera group a large quantity of both secondary xylem and phloem is formed by every new interxylary cambia. Xylem and phloem originated from both cambial types have features similar to those of other Malpighiaceae lianas, except for the absence of septate fibers and perforated ray cells, the presence of stratified phloem and prismatic crystals in the phloem of the Banisteriopsis nummifera group and a concentric ring of cortical secretory cells characteristic of Stigmaphyllon. The cambial variant interxylary cambia is here named for the first time, and this new term is proposed to unmistakably denote its origin from within the secondary xylem, which is likely a synapomorphy for these two Malpighiaceae lineages. (AU)

• FAPESP's process: 13/10679-0 - Ontogenetic, functional and evolutionary aspects of the cambial variants in tracheophytes
• Grantee: Veronica Angyalossy
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• FAPESP's process: 12/01099-8 - Ontogeny, phylogeny and evolution of the vascular system of lianas
• Grantee: Marcelo Rodrigo Pace
• Support Opportunities: Scholarships in Brazil - Doctorate