Citation
Ramlan, Nurhana Nadia
(2019)
Effects of phloroglucinol and resorcinol on In vitro vegetative growth enhancement and lethal browning reduction in lang banana.
Masters thesis, Universiti Putra Malaysia.
Abstract
Browning is
ue culture industry. The formation of browning is due to the formation of dark exudates around
explants, in which it can inhibit explant proliferation. Phenolic compounds such as phloroglucinol
(PG) and resorcinol are known to have an ability to reduce browning in food and
cosmetic products. Hence, both phenolics were used in this study to determine their capability to
reduce browning and at the same time to enhance growth of in vitro Lang banana. The total
soluble protein content, gene expression level of antioxidant (catalase (CAT), ascorbate
peroxidase (APX) and peroxidase (POD)), browning- inducing (phenylalanine ammonia lyase
(PAL) and polyphenol oxidase (PPO)) and lignin-biosynthetic (MYB31, MYB58, cinnamoyl coA
reductase (CCR), catechol-O- methyltransferase (COMT), cinnamyl aldehyde dehydrogenase
(CAD) and p– coumarate hydroxylase (C3H)) genes as well as their enzymes activities
were also observed on the early stage of browning of Lang banana explants grown on selected media.
To achieve the objectives, Murashige and Skoog (MS) basal media supplemented
with B5 vitamin, different concentrations of phenolics (PG or resorcinol),
different concentrations of cytokinins (6-benzylaminopurine (BAP) or kinetin) and auxin
(α-naphthalene acid (NAA)) were used. The growth of each explant was recorded by determining the
number of shoots, number of buds and number of roots every week for 12 weeks. The visual degree of
browning was also recorded. The highest percentage of explants belong to mild browning was
observed from media containing NAA (0 to 0.013 mM) + resorcinol at range of concentrations of
1.0 to 2.5 mM (60 to 100%). Meanwhile, the combination of NAA (0 to 0.013 mM) + PG at range of
concentrations from 1.0 to 2.5 mM showed lower percentage of mild browning (0 to 40%) compared to
NAA + resorcinol media. The medium containing 0.023 mM kinetin + 0.5 mM resorcinol produced the
highest mean number of shoots (6.2±1.20). Meanwhile, the medium containing 0.022 mM BAP + 0.5 mM PG
showed the highest bud proliferation (7.8±0.45). The medium containing 0.005 mM NAA + 1.5 mM PG
produced the highest number of roots (30.4±1.43). Among the media tested six media were
categorized into mild (MS medium containing 0.008 mM NAA + 0.5 mM PG (MBPG) and MS medium
containing 0.005 mM NAA + 2.0 mM resorcinol (MBR) media), intermediate (MS medium containing 0.023 mM kinetin + 0.011 mM NAA +
0.5 mM PG (IBPG) and MS medium containing 0.023 mM kinetin + 0.5 mM resorcinol (IBR)) and severe
browning inducing media (MS medium containing 0.022 mM BAP +
0.013 mM NAA + 2.5 mM PG (SBPG), and MS medium containing 0.022 mM BAP +
0.013 mM NAA + 2.5 mM resorcinol (SBR)). The highest total soluble protein content was observed in
SBPG explant (40.46±0.01 mg/g FW). The highest CAT (356.26±0.02 µmol/min/mg) and APX
(5893.18±0.20 µmol/min/mg) activities were observed in MBPG explant. Meanwhile, the
highest POD, PPO, C3H and PAL activities were determined in SBR explants
(13849.88±0.06, 2639.52±0.02, 1332.38±0.00 and 132.57±0.01 µmol/min/mg, respectively). Among
the genes tested, the highest PAL expression was found in SBPG explant (225.31-fold).
Meanwhile, the highest expression of APX and PPO was observed in IBR explants (4887.9- and
37.33-fold, respectively). The POD, COMT and CCR expression were up-regulated in MSO9
explant (49.57-, 302.49- and 89.30-fold, respectively), while the highest expression of C3H, CAD
and CAT (44.36-, 11.22- and 29.33-fold, respectively) were observed in MBR explant. The expression
of MYB31 was highly expressed in MBPG explant (9.07- fold) while the expesssion of MYB58 was found
the highest in MSO7 explant (19.39- fold). Hence, the incorporation of the PG and
resorcinol into different media formulations is proven can reduce browning and improve
proliferation of in vitro Lang banana. The presence of antioxidant, browning-inducing and
lignin-biosynthetic enzymes as well as their mRNA transcripts in the early browning explants
suggest their involvement in scavenging free radical, reducing browning and enhancing
lignin production. Therefore, the best media produced from this study can help plant tissue culture
laboratories to mass produce Lang banana seedlings. The analyzed genes can be used as biomarker to
develop browning resistant Lang banana in the near future.
Download File
Additional Metadata
Actions (login required)
![View Item View Item](/style/images/action_view.png) |
View Item |