Micropropagation and Effect of Growth Retardants on Selected Species of Melastomataceae
This study consists of four parts. The first part was to develop an efficient in vitro micropropagation protocol for Melastoma malabathricum, Melastoma decemfidum, Melastoma dodecandrum and Tibouchina semidecandra. These plants are locally known as 'senduduk'. Nodal segment and shoot ti...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2005
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/51/1/1000548922_t_FBSB_2005_1.pdf |
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| Summary: | This study consists of four parts. The first part was to develop an efficient in vitro
micropropagation protocol for Melastoma malabathricum, Melastoma
decemfidum, Melastoma dodecandrum and Tibouchina semidecandra. These
plants are locally known as 'senduduk'. Nodal segment and shoot tip of each
species were used as explants for shoot initiation. Shoot tip was a more suitable
explant for M. malabathricum, M. dodecandrum and M. decemfidum shoot
initiation performed in full strength Murashige and Skoog (MS) medium
supplemented with 30 μM 6-benzylaminopurine (BAP), while nodal explant was
chosen for T. semidecandra shoot initiation in full strength MS medium
supplemented with 20 μM BAP.
Shoot multiplication and elongation was optimal in half strength MS medium
supplemented with 6 μM BAP for T. semidecandra, 9 μM BAP for M.
malabathricum and 12 μM BAP for M. decemfidum while M. dodecandrum
required quarter strength MS medium supplemented with 3 μM BAP. Shoots
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cultured on MS medium without any growth regulators supplementation was
found to have higher in vitro rooting compared to medium supplemented with
naphthalene acetic acid (NAA), indole butyric acid (IBA) and indole acetic acid
(IAA). Full strength MS medium was suitable for in vitro rooting of T.
semidecandra and M. decemfidum, opposed to half strength MS medium for M.
malabathricum and quarter strength MS medium for M. dodecandrum. Rooting
in the solid medium was better than liquid medium. A higher percentage of
plantlets survived when they were acclimatized for one week compared to
plantlets that were directly transferred from tissue culture medium to the soil.
The second part of this study was to regenerate shoots directly from the leaf,
petiole and internode explants of M. malabathricum. Explants obtained from the
most apical part of the plant formed a higher number of shoots compared to those
below the apical end. Quarter strength MS medium was the most suitable
medium strength for shoot regeneration of all explants tested. The highest
number of shoots was formed from the leaf explant at 9 μM BAP, followed by
petiole at 6 μM BAP, and internode at 9 μM BAP.
The third part of this study was to regenerate shoots from leaf-, petiole- and
internode-derived calli of M. malabathricum. A suitable callus induction medium
was found to be a full strength MS medium supplemented with 2.5 μM dicamba
and 2.5 μM kinetin for leaf explant, 10.0 μM NAA and 2.5 μM BAP for petiole
explant, and 10.0 μM NAA and 2.5 μM kinetin for internode explant. Full
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strength MS medium supplemented with 5.0 to 7.5 μM BAP alone had induced
multiple shoots from the leaf-derived callus compared to 2.5 to 5.0 μM BAP for
petiole-derived callus. A combination of 0.5 μM NAA and 5.0 μM BAP,
however, was found to enhance shoot formation from the petiole-derived callus
compared to when 5.0 μM BAP was used alone.
The final part of this study was to evaluate the effects of growth retardants on
vegetative growth and the flowering of M. malabathricum, M. decemfidum and T.
semidecandera. Growth retardants (paclobutrazol and flurprimidol) significantly
reduced the plant size, induced early flowering and increased the number of
flowers formed unlike the untreated plants. Paclobutrazol applied at 200 mg/L
(w/v) was found to be suitable for M. malabathricum compared to 300 mg/L
(w/v) for M. decemfidum. Flurprimidol applied at 50 mg/L (w/v) concentration
was suitable for T. semidecandra. |
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