Vegetative propagation of Holarrhena pubescens, a wild tropical medicinal plant: effect of indole-3-butyric acid (IBA) on stem cuttings

Abstract

The present study investigated the rooting ability and growth performance of juvenile single-node leafy stem cuttings of Holarrhena pubescens, collected from two mature mother trees preserved in the hill forests of Chittagong District, Bangladesh. The rooting ability of cuttings was studied with 0, 0.1%, 0.2% and 0.4% indole-3-butyric acid (IBA) treatments. The better rooting response was observed with 0.1% IBA, but was insignificant compared to other treatments. The mean number of roots and length of the longest root of cuttings in different treatments showed no significant difference. After transfer to the polythene bags from a nonmist propagator, rooted cuttings treated with 0.4% IBA demonstrated the highest (50.00 \( \underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{ \pm } \) 0.78%) survival capacity. Regarding initial growth of established rooted cuttings (stecklings) over a 90 d period, the increment of stem length of stecklings under T2 (10 g Urea, 20 g TSP, 10 g MOP dissolved in 2 L water) and leaf area expansion of stecklings under T1 (10 g Urea, 20 g TSP, 10 g MOP dissolved in 1 L water) was significantly higher (p < 0.05) compared with that under T0 (no fertilizer). The increment of collar diameter and root biomass production varied insignificantly among different fertilizer concentrations, although stecklings under T2 showed the better performance. The results suggest that rooting juvenile single-node leafy stem cuttings can be an effective mean of regenerating H. pubescens. The application of 0.1% IBA or without IBA is recommended for rooting juvenile leafy stem cuttings. Application of fertilizer appears necessary for subsequent growth of stecklings in polythene bags.