ABSTRACT
The objective for this study was to determine the most efficient chlorine concentration in order to protect explants in tissue culture from contamination. Leaf blade explants of 1 cm2 were used. The leaves were washed with tap water for 5 minutes and then washed 3 times with distilled water. The explants were placed in a laminar air flow chamber followed by immersion in 70% alcohol for 30 minutes and then washed 3 times with sterile distilled water, followed by 20 minutes immersion in a sodium hypochloride comercial solutions with active chlorine concentrations of: 0.0%, 0.5%, 1.0%, 1.5% and 2.0%. Still inside the laminar air flow chamber, the explants were placed in test tubes (containing MS medium) with the adaxial face in contact with the medium. The experimental design was completely randomized with 5 replications of 5 test tubes per plot, each containing one innoculated explant. The explants in the test tubes were kept in the dark in a growth chamber at 25 ± 2º C during a 14-day period, then evaluated for contamination. There were observed significant differences between species of araceas with regard to their responsiveness to the different concentrations of sodium hypochloride, which supports the difference in concentration to be used specifically for each one. It is advisable to always use a NaOCl solution having the lowest effective concentration of active chlorine to avoid damage to the explants.
KEY WORDS
Araceas; ornamental plants; disinfection; sodium hypochloride