Previous studies have reported very low survival rate in vitro of youn
g leaf explants of Impatiens flanaganiae (a rare plant of medicinal an
d horticultural importance) as they suffered early senescence and subs
equent death. B5 medium supplemented with 2.6 mg l(-1) 2,4-D and 1.25
mg l(-1) BA medium, (recommended for callus induction from leaf explan
ts of I. flanaganiae) was modified by the addition of 0.0 mmol l(-1) 1
.02 mmol l(-1) or 5.1 mmol l(-1) Ca (treatment 1, 2 & 3 respectively)
to study the effect of Ca on improving callus induction in this specie
s. Treatment 3 induced callus formation in 3 weeks time, prevented ear
ly senescence and enhanced the survival rate of explants to more than
80%. Peroxidase (POD) activity in explants cultured on all media was g
reater than in intact leaves. Weekly analysis of POD activity in expla
nts cultured on medium 3 Showed an initial low level of peroxidase, wh
ich turned highest by the 5(th) week in comparison to the explants on
other media.