Secondary xylem development in Arabidopsis: a model for wood formation

Abstract

Our understanding of the molecular controls regulating the identity of the vascular cambium and the development of secondary xylem and phloem have not yet benefited much from the use of Arabidopsis as a genetic system. Under appropriate growth conditions Arabidopsis undergoes extensive secondary growth in the hypocotyl, with the development of both a vascular and a cork cambium. The secondary xylem of the hypocotyl develops in two phases, an early phase in which only vessel elements mature and a later stage in which both vessel elements and fibres are found. During this second phase the secondary xylem of Arabidopsis closely resembles the anatomy of the wood of an angiosperm tree, and can be used to address basic questions about wood formation. The development of the vascular cambium and secondary growth in Arabidopsis hypocotyl is described and its utility as a model for wood formation in trees is considered.

Cytokinins are central regulators of cambial activity

“…The cambium is later initiated from the procambium and produces cells required for secondary thickening (18). Arabidopsis undergoes similar thickening processes as trees, and it has a great advantage in that many mutants and transformants are readily available.…”

“…Although Arabidopsis generally finishes its growth within 2 months, it typically undergoes secondary growth similar to trees and therefore can be a useful model plant for studying secondary growth (18). In Arabidopsis, inflorescence stem thickness depends both on the size of the shoot apical meristem and on the secondary thickening growth, the latter of which involves cell division in the cambial zone, cell enlargement, and wall synthesis.…”

Genomics, Domestication, and Evolution of Forest Trees

“…DNA sequence relationships support the relatively recent evolution of woody plants found on islands descending from continental herbaceous founders (Böhle et al 1996;Helfgott et al 2000). Arabidopsis thaliana, typically small, fast growing, and herbaceous, can be induced to form secondary xylem (wood) by delaying flowering and senescence (Lev-Yadun 1994;Dolan and Roberts 1995;Chaffey et al 2002). The genes that determine the woody growth habit appear not to be unique to woody plants but are likely to be common genes, regulated in different ways (Groover 2005).…”

Expression of Glycosyl Hydrolases in Lignocellulosic Feedstock: An Alternative for Affordable Cellulosic Ethanol Production

“…It is worth noting that there are significant differences between cell wall structure and composition of potential biofuels feedstocks, let alone differences from model plants. Arabidopsis is distinctive from woody plants in terms of physiology and genetics [109,110] and has a significantly lower proportion of secondary cell wall than woody plants [111]. Additionally, the cell wall composition is divergent between species, whether model species or potential feedstocks [112].…”