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An investigation into the potential of developing an in vitro method for propagating strelitziaceae
Author(s)
North, Jade Joan
Date Issued
2011
Type
Thesis
Publisher
Cape Peninsula University of Technology
Abstract
A study was conducted to investigate the effects of: i) various media compositions and
wounding treatments on the in vitro germination, growth and regeneration of Strelitzia
reginae plantlets derived from zygotic embryos, ii) antioxidants, plant growth regulator (PGR)
concentrations and plant tissue wounding treatments on phenolic compound production.
One experiment consisted of 8 medium types including different combinations of Murashige
and Skoog (MS) medium strength, activated charcoal and vitamin supplements. Twelve
replicates were used for each treatment. In another experiment, germinated plantlets were
subjected to 2 wounding treatments; (unwounded explants (control) and explants
longitudinally sectioned through the apical meristem). The explants were transferred to ten
different regeneration media consiting of different concentrations and combinations of auxin
and cytokinin supplements and antioxidants. Ten replicates were used for each treatment.
Results indicated the positive role of activated charcoal (AC) in reducing oxidative browning
of embryo explants. The highest germination rate of embryos was observed in media
containing AC without vitamin supplementation. Germination significantly decreased with the
addition of vitamins. With regard to effects of various media compositions and wounding
treatments on in vitro growth and regeneration of Strelitzia, significant results were achieved
with 1-naphthalene acetic acid (NAA) and 6-benzylaminopurine (BAP) concentrations on
explant discoloration and callus formation. The antioxidant treatments, activated charcoal
(AC) and ascorbic acid (AA) significantly affected explant discoloration, the induction of
callus and the length of roots developed. Wounding treatments affected plant height,
increased explant height and callus formation. Interactions between higher NAA and BAP
concentrations together with wounding resulted in the most effective treatment in reducing
explant discoloration at the media contact point. Furthermore, results showed the various
NAA and BAP concentrations to significantly affect phenolic exudation. The media containing
the highest PGR concentration resulted in the highest phenol content. AC significantly
reduced the total phenol content of media by 53%, compared with AA. Phenolic exudation
was significantly increased as a result of explant wounding. Various interactions between the
NAA and BAP concentrations, antioxidants and wounding affected phenolic exudation and
the total phenol content of media.
This study provides insight into the contributing factors and methods of overcoming the major
problem of phenolic oxidation and promoting the in vitro growth and regeneration of Strelitzia.
wounding treatments on the in vitro germination, growth and regeneration of Strelitzia
reginae plantlets derived from zygotic embryos, ii) antioxidants, plant growth regulator (PGR)
concentrations and plant tissue wounding treatments on phenolic compound production.
One experiment consisted of 8 medium types including different combinations of Murashige
and Skoog (MS) medium strength, activated charcoal and vitamin supplements. Twelve
replicates were used for each treatment. In another experiment, germinated plantlets were
subjected to 2 wounding treatments; (unwounded explants (control) and explants
longitudinally sectioned through the apical meristem). The explants were transferred to ten
different regeneration media consiting of different concentrations and combinations of auxin
and cytokinin supplements and antioxidants. Ten replicates were used for each treatment.
Results indicated the positive role of activated charcoal (AC) in reducing oxidative browning
of embryo explants. The highest germination rate of embryos was observed in media
containing AC without vitamin supplementation. Germination significantly decreased with the
addition of vitamins. With regard to effects of various media compositions and wounding
treatments on in vitro growth and regeneration of Strelitzia, significant results were achieved
with 1-naphthalene acetic acid (NAA) and 6-benzylaminopurine (BAP) concentrations on
explant discoloration and callus formation. The antioxidant treatments, activated charcoal
(AC) and ascorbic acid (AA) significantly affected explant discoloration, the induction of
callus and the length of roots developed. Wounding treatments affected plant height,
increased explant height and callus formation. Interactions between higher NAA and BAP
concentrations together with wounding resulted in the most effective treatment in reducing
explant discoloration at the media contact point. Furthermore, results showed the various
NAA and BAP concentrations to significantly affect phenolic exudation. The media containing
the highest PGR concentration resulted in the highest phenol content. AC significantly
reduced the total phenol content of media by 53%, compared with AA. Phenolic exudation
was significantly increased as a result of explant wounding. Various interactions between the
NAA and BAP concentrations, antioxidants and wounding affected phenolic exudation and
the total phenol content of media.
This study provides insight into the contributing factors and methods of overcoming the major
problem of phenolic oxidation and promoting the in vitro growth and regeneration of Strelitzia.
Additional information
Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2011
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