The effect of charcoal on tissue morphogenesis in vitro.
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Date
2000
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Abstract
The effect of activated charcoal, autoclaving and culture media on sucrose
hydrolysis in tissue culture media was investigated. Activated charcoal acidified an
aqueous sucrose (5%) solution and culture media by about 1 to 2 units after
autoclaving . Sucrose hydrolysis in tissue culture media and/or aqueous sucrose
(5%) solutions containing activated charcoal (buffered to pH 5.8) was dependent
on both the hydrogen ion concentration (pH) and autoclaving. After autoclaving,
70%, 56% and 53% sucrose hydrolysis were respectively recorded in a 5.0%
sucrose solution, Murashige and Skoog (MS) and Gamborg B5 (B5) liquid media
in the presence of 1.0% activated charcoal, added before autoclaving . In the
absence of activated charcoal, autoclaving resulted in about 20% of the sucrose
being hydrolysed
The adsorption of 2, 4-dichlorophenoxyacetic acid (2,4-D) by activated
charcoal from methanol and aqueous solutions was determinated using HPLC. The
amount of the added 2,4-D decreased in both methanol and aqueous solutions in
the presence of activated charcoal, compared with those in the absence of
activated charcoal. In methanol and aqueous solutions, activated charcoal used
at the level of 0.1% significantly reduced 2,4-D. About 68.4% and 60.9%
respectively of the added 2,4-D was adsorbed by activated charcoal (1.0%) from these solutions. The changes of inorganic elements in MS-salt solutions, in the
presence of activated charcoal, were analysed by SEM-EDX. The concentrations
of magnesium (Mg), calcium (Ca), iron (Fe) and zinc (Zn) deceased in the
presence of activated charcoal, while the concentrations of potassium (K), copper
(Cu), manganese (Mn), phosphorus (P), and sulphur (S) increased in the MS salt
solution in the presence of activated charcoal compared with no activated charcoal
in the medium. This suggests that activated charcoal adsorbed calcium,
magnesium, iron and zinc and released copper, manganese, phosphorus and sulphur.
Rooting occurred when 7-day-old seedling hypocotyls of Daucus carota L.
Cape Market were placed on MS medium supplemented with 2,4-D, and IAN/NAA
in the presence of activated charcoal. Hypocotyls did not produce roots on the 2,4-D
containing media in the absence of activated charcoal. The roots were
produced polarly on the NAA/IAA-containing media in the presence of activated
charcoal. No-polarity of root formation was observed on media supplemented with
NAA/IAA without activated charcoal. Different responses of hypocotyls to a series
of 2,4-D concentrations (0.5, 1.0, 3.05.0, 8.0, and 10.0 mg l ¯¹) were observed on
media supplemented with 0.02, 0.1 and 0.5% activated charcoal. In the NAA/IAA containing
media in the presence of activated charcoal, root number per hypocotyl
decreased. Root number perhypocotyl, on the media supplemented with NAA and IAA, increased when hypocotyls were pre-cultured on MS medium supplemented with 2,4-D (1.0 mg l ¯¹)
for 2-3 days. When hypocotyls were pre-cultured on a 2,4-D containing
MS medium for 5 days, embryos emerged from the hypocotyls directly
on the medium supplemented with 2,4-D in the presence of activated charcoal. Addition of activated charcoal to MS medium supplemented with 2,4-D
resulted in somatic embryogenesis of Daucus carota. Somatic embryos were not
formed on the medium in the absence of activated charcoal. In suspension culture,
the incorporation of 0.01 to 1.0% concentrations of activated charcoal to the MS
medium, irrespective of 2,4-D, increased the number of somatic embryos
produced. The maximum number of somatic embryos were produced with 1.0%
activated charcoal. Further development of embryos of Daucus carota occurred
on the media in the presence of activated charcoal, and the embryos subsequently
regenerated normal plantlets. Abnormal somatic embryos followed the addition of 3.0% activated charcoal to the medium.
Description
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2000.
Keywords
Plant micropropagation., Plant cell culture., Daucus carota--Micropropagation., Plant growing media., Carbon, Activated., Theses--Botany.