The development of kino veins in Eucalyptus obliqua L'Hérit

Abstract

Kino veins develop in a layer of traumatic parenchyma which is laid down shortly after the stimulus to vein formation is given (in these experiments this occurred about 15 days after wounding), and groups of cells in this traumatic parenchyma accumulate large quantities of polyphenols. At particular foci, groups of cells containing polyphenols break down and form a tangential network of ducts into which the contents of the cells are released. These contents form the kino. At about the same time, the cells surrounding the future veins divide repeatedly and form a peripheral cambium. The derivatives of the peripheral cambium grow and accumulate polyphenols, and eventually they break down also and their contents augment the quantity of kino already present. Eventually (about 49 days after wounding in these experiments) the peripheral cambium produces a layer of derivatives which become suberized in the form of a typical periderm.

Although the polyphenols in E. obliqua are of the ellagitannin type, those accumulated in the traumatic parenchyma and the veins contain a large proportion of leucoanthocyanins. Leucoanthocyanins accumulated right from the earliest stages of vein development.