Tissue culture of selected indigenous monocotyledons.
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Date
1988
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Abstract
Components of the South African indigenous flora are disappearing at an alarming
rate, due to pressures on land use. The flora is protected by proclamation of reserves
and conservation legislation, however these measures can never be wholly
successful. For these reasons, methods for propagting Clivia miniata, Gloriosa
superba and Sandersonia aurantiaca using in vitro techniques were investigated.
The highly sought after Clivia miniata var citrina can be successfully cultured
using fruit and floral explants. Use of these explants may limit the number of
plants produced in culture due to the seasonal nature of flowering. Gloriosa superba
and Sandersonia aurantiaca can be propagated using corm explants, with subsequent
in vitro stimulation of cormlet formation. To establish a successful tissue culture
procedure an integrated approach to all aspects of the culture is necessary. Sterilization
techniques should be empirical and specific for each species and explant.
The most critical factor in establishing a culture technique is the choice of a
suitable explant. Without a suitable explant the success of the culture procedure
may be severely limited. Nutritional and environmental variation may modify
the explant response in culture, but initial culture response can be directly related
to the origin of the explant, particularly, size, time of the year, age and physiological
status.
Since the discovery of colchicine in Gloriosa by CLEWER, GREEN and TUTIN
(1915) a number of researchers have put forward the idea that Gloriosa would
serve as a source of colchicine. The present trend in biochemical production is
via artificial synthesis, however many desirable compounds still have to be extracted
from plant material for biochemical production. The utilization of plant cells that are cultured in vitro provides a viable alternative to the problems involved
in the production of chemical compounds.
Levels of colchicine in Gloriosa and Sandersonia are very similar, in the range
of ± 0,9%. From evidence presented by BELLET and GAIGNAULT (1985), levels
of colchicine in the two study species is much higher than the recorded level (0,62%)
of Colchicum. This higher level of the alkaloid makes these two plants a viable
source for commercial colchicine production.
Levels of colchicine recovered from in vitro grown roots and callus was 10 - 20
times lower than that found in -in -viv-o tissue. Levels of colchicine extracted from
plantlets grown in vitro was the same as that normally recorded for parent tissue.
Higher levels of colchicine in malformed roots adds to the evidence that differentiation
increases colchicine production in Gloriosa tissue in vitro.
It has been shown that Gloriosa and Sandersonia tissue can synthesize colchicine
in vitro. The extent to which the cells synthetic capacity can be enhanced has
yet to be determined. However, research into speedier and more wide ranging
methods for metabolite production in culture is receiving attention throughout
the world.
Description
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1988.
Keywords
Plant tissue culture., Plant micropropagation., Monocotyledons--Micropropagation., Gloriosa superba--Micropropagation., Clivia miniata--Micropropagation., Sandersonia aurantiaca--Micropropagation., Theses--Botany.