Diverse forms of xylem-like cells and strand formation in Xylogenic Eucalyptus bosistoana callus culture

Abstract

In vitro xylem induction system is a basic tool in physiological, biochemical, and molecular studies of secondary cell wall formation, lignin biosynthesis and deposition associated with tracheary element formation. Eucalyptus bosistoana is a Class 1 durable hardwood tree species, selected by the New Zealand Dryland Forest Initiative for good quality wood and high adaptability to the NZ growing conditions. Xylogenic E. bosistoana callus culture was established and up to 40% of the callus cells were xylem-like cells (XLCs) which may have differentiated from small, cytoplasmically dense or compact dividing, and exhibited increased lignin contents during culture. The eucalyptus XLCs showed diverse sizes, patterns of secondary cell wall thickenings similar to the xylem cells in the young shoots and organized development including cell–cell connections of the XLCs to form xylem strands. This is the first report of the organized development of XLCs in E. bosistoana callus culture.