Screening of topical sterilants for shoot apex culture of Acacia mearnsii

Abstract

The surface sterilisation procedure is of integral importance to any micropropagation technique. This process should do the least amount of plant damage, whilst reducing microbial contamination to an acceptable level. The objective of this research was to investigate alternative sterilisation agents to the dangerous chemical mercuric chloride (HgCl2), and to determine the effect of sterilant exposure time on shoot apex culture of Acacia mearnsii. Explants were cultured on MS medium supplemented with 2.0 mg l–1 BA and monitored for 21 d for signs of contamination and shooting. Household bleach (NaOCl), diluted 1:3 in water, resulted in decontaminated explant levels not significantly different to the 0.2% HgCl2 treatment and resulted in shoot development levels significantly higher than the 0.2% HgCl2 treatment. There was no significant effect of sterilant exposure time on decontaminated explant levels, whilst the shortest exposure time resulted in significantly higher shooting levels than the other two time periods tested.