Abstract:
Exacum trinervium (Gentianaceae) is a threatened endemic medicinal and
ornamental plant for which ex-situ cultivation has been recommended as a
conservation strategy. Although the seeds germinate, seedling growth is poor
and therefore difficult to maintain under captive environment. The effect of presowing
BAP (6 -Benzylaminopurine) treatment to enhance the seed germination
and seedling vigour of E. trinervium was examined. BAP concentrations of 1, 2
and 3 mgL' 1 as pre-sowing treatments under 18, 24 and 30 hrs exposure
durations were used in laboratory and nursery conditions. Control experiment
was maintained with distilled water. BAP concentrations of 2 and 3 mgL' 1 under
24 hrs exposure duration showed significant effect (P<0.05) on increasing
seedling dry weight and seedling vigour index compared to the control. There
was no significant effect of BAP treatpients on seed germination percentage
under laboratory and nursery conditions. Twenty four hour exposure duration
resulted in lowest mean germination time under nursery conditions. The effect of
BAP concentration and exposure duration is significant (P<0.05) on number of
leaves, plant height, root length, number of primary roots, dry weight and fresh
weight of E. trinervium. The present study suggests that BAP treatment may
improve seedling emergence and plant development in greenhouses.
