Abstract:
Munronia pinnata (Wall). Theob is a valuable medicinal
plant which is widely used in Ayurvedic medicine in Sri Lanka.
Due to over exploitation and low percentage of seed germination
of M. pinnata it has become necessary to adopt ex situ
conservation methods via in vitro propagation techniques. The
objectives of this study was mass propagation, greenhouse
establishment and comparison of in vitro propagated plants with
seed raised plants. Callus cultures were initiated from different
explant types such as apical buds, nodal segments, petioles,
petals and leaf discs in Murashige and Skoog (MS) medium
supplemented with 1.1 mg L 1 2,4- dichlorophenoxy acetic acid
(2,4-D) and 0.5 mg L 1 benzyl amino purine (BAP) at 25 ± 1°C
in complete darkness. Leaf discs (6.0 mm) showed significantly
higher calli production (mean fresh weight 0.167± 0.04 g) than
other tested explants. The best growth regulator combination for
callus initiation was 1.1 mg L"12,4-D and 0.3 mg L"1 BAP which
produced a mean of 0.30 ± 0.06 g callus while other treatments
produced lesser amount of callus. Leaf discs taken from first
fully opened leafs, produced the highest amount of callus (0.06
± 0.01 g) and a decreasing trend was observed with increased
maturity of the leaf. Tissues along the midrib area have a higher
potential to give high yield of callus. Shoot proliferation was
higher (32.9 ± 2.2) in MS medium containing 3.0 mg L 1
naphthalene acetic acid (NAA) and 3.0 mg L 1 BAP. Light
intensity at 3000 lx showed significantly higher number of shoots
(33.4 ± 2.84) than other tested light intensities. Half MS minerals
supplemented with 0.2 mg L"1 indole acetic acid (IAA) was the
most effective treatment for root induction (75%) with the highest
mean root length (15.05 ± 0.5 mm) and 3.15 ± 0.03 of mean
number of roots. A suitable potting mixture for acclimatization
was determined using different ratios of compost and sand. Higher
percentage of survival (60%) was achieved with compost: sand
1:3. When morphological features of seed raised plants were
- compared with tissue cultured plants, mean height increment was
higher in seed raised plants while mean number of leaves washigher in tissue cultured plants and branching habit was observed
only in tissue cultured plants. A comparison of physiological
parameters between the two types of plants showed that the rate
of photosynthesis was higher in tissue cultured plants whereas
stomatal resistance was higher in seed raised plants.
