Anatomical Changes Which Occur in Cuttings of Agathis australis (D. Don) Lindl 1. Wounding Responses

The basal and sub-basal regions in cuttings of Agathis australisundergo a complex series of anatomical changes. Many of theseare categorized as wound responses and include cell divisionsassociated with the cut base and the proliferation of tracheidsand phloem which arise in the interfascicular region about 4mm above the cut base. The vascular tissue arcs outwards anddownwards through the cortex. It may develop as isolated strandsonly a few cells wide or as sheets involving a number of cells.The precise pattern of vascular development appears to be determinedby its extent at the point of origin and by the presence ofobstacles such as primary and secondary resin canals which arelocated to the outside of the vascular bundles in the stem.Secondary resin canals are produced only in the rooting zonein cuttings that show extensive cell division. They arise schizogenouslyand do not form an interlinking network. Root primordia arise in the cortex at the end of isolated strandsof newly developed vascular tissue. Primordia never form inassociation with sheets of tracheids or after the convergenceof strands. In some cases virtually the entire sub-base is filledwith vascular tissue as a result of cell division and the differentiationof parenchymatous tissue. Root primordia never appear in thissituation. Agathis australis (D. Don) Lindl, kauri, cuttings, wound responses, vascular development, resin canals, root primordia, cellular differentiation