Effect of activated charcoal and ascorbic acid on in vitro morphogenesis and o-dihydroxyphenols content in Paphiopedilum insigne

Phenolic compounds limit micropropagation of many orchids in vitro. The aim of the study was to estimate the effect of activated charcoal (AC);1, 2 or 4 g/L) or ascorbic acid (AA; 10, 20 or 30 mg/L) added to the half strength MS medium on the growth and o-dihydroxyphenols content in Paphiopedilum insigne in vitro. A positive effect of AC on the shoot and root formation has been found. The highest multiplication rate (5.6 shoots/explant) and rooting frequency were obtained on medium containing 2 g/L of AC. However, AC reduced the leaf number as compared to the control. The lowest content of o-dihydroxyphenols was marked in Paphiopedilum insigne leaves when the shoots were grown on medium with 10 mg/L AA, followed by AC at 1 or 2 g/L.