Photoautotrophic micropropagation of Banksia

Summary of final report on the Australian Flora Foundation funded project:

Photoautotrophic micropropagation of Banksia
John Godfrey & Rob Cross
Royal Botanic Gardens Melbourne, Birdwood Avenue, South Yarra, 3141

Grant Details    Final Report

The objective of this project was to develop a tissue culture propagation method for Banksia species. Banksias are an important component of the Australian cut flower export industry, but most plants are derived from seed, with consequent problems of variability. Tissue culture methods offer the prospect of rapid multiplication of selected superior forms. Although there are a few reports of culture of Banksia species, no technique giving good ex vitro survival has been developed. The initial aim of the project was to look at photoautotropic propagation of these species, but early in the work it became apparent that a major barrier to successful tissue culture was surface de-contamination of the species. Hence the focus was changed into developing a reliable method for introducing Banksia into culture.

The method finally developed involved taking terminal shoots of Banksia coccinea, about 150mm long, from greenhouse grown plants, trimming off the leaves, and placing the stems into 0.01M HCl with 3 drops/500ml of Tween 80® with gentle agitation for 3 minutes, then transfer to 1% available chlorine solution for 10 minutes with constant agitation; then to sterile 2.4mM citric acid solution for 5 minutes. The sections were rinsed once and stored in sterile de-ionised water. Seventy-five percent of explants survived, and remained green and viable after surface sterilisation using this treatment, and subsequent placement on tissue culture medium. A higher percentage of explants survived on ½ M & S although bud expansion and growth was observed to be best on WPM.

This procedure offers a fast, simple, safe and effective means of surface de-contamination which does not damage plant cells or destroy surface integrity. This surface sterilisation method has enabled a number of small trials to be undertaken to determine an optimal in vitro medium for the initiation and multiplication of Banksia coccinea. Although long-term in vitro survival and multiplication have been unsuccessful to date, a basis for a full-time research project has been established. The procedure offers promise for the surface de-contamination of other woody species.