Faculty of Natural and Agricultural Sciences
School of Agricultural and Food Sciences
Department of Plant Production and Soil Science
Selected Highlights from Research Findings
Research into bio-fuels is being done in the Department of Plant Production and Soil Science, under the management of Prof Elsa du Toit. Contracts related to possibilities in the bio-fuels industry of South Africa have been delivered to the Department of Agriculture and the Department of Trade and Industry.
A two-year feasibility study has been completed on Jatropha curcas as a potential biodiesel tree crop, in the Mafikeng area of South Africa. Plant propagation protocols for potential indigenous trees for the bio-diesel industry have also been done. Current research is aimed at the optimization of horticultural practices for potential bio-diesel tree crops in South Africa
Contact person: Prof ES du Toit.
The University has successfully established a Potato Research Programme funded by Potatoes South Africa. The Department of Plant Production and Soil Science coordinates the programme that began in 2005 with seven projects involving scientific disciplines from Entomology, Plant Pathology, Consumer Science and Plant Production.
One project deals with the stimulation of sprout growth on fresh, dormant potato seed tubers, which is a critical step in timeous seed certification. The topic of tuber dormancy has been under investigation for almost a hundred years, but in spite of the mass of accumulated scientific information, it is still practically impossible to force a fresh tuber to sprout.
A promising procedure developed at the University utilizes a combination of gibberellins and cytokinins. Provided water is available to the developing sprouts, dormant tubers harvested from plants still growing can be induced to sprout within four days, with vigorous sprouts present after 10 days when sprout growth slows down.
The next challenge is to find a way to sustain sprout growth and ensure plant establishment. Apart from hormonal checkpoints in the cell cycle of the buds, sprouting is probably also controlled by blockage of plasmodesmata with callose, thus prohibiting transport of stored assimilates and other resources to the developing sprouts.
The integrity of cell membranes of fresh tubers may be an additional factor limiting cell-to-cell transport. Application of oxidants yielded promising results in terminating tuber dormancy, possibly by breaking down of callose plugs and affecting membrane integrity
Contact person: Prof PS Hammes.
South Africa’s national flower, the King Protea (Protea cynaroides), is an important cut flower for the floriculture industry. It is in high demand and obtains exceptionally high prices on the export markets. A major constraint for producers is that conventional propagation by seeds and stem cuttings is unreliable and slow.
With recent research conducted at the Department of Plant Production and Soil Science under the supervision of Proff Elsa du Toit and Charl Reinhardt, unique in vitro propagation protocols for P. cynaroides were developed using in vitro zygotic embryo culture, micrografting and somatic embryogenesis. Significant improvement in the rooting of cuttings was achieved through blanching. The relationship between starch and phenolic compound levels and rooting of cuttings was established. A final discovery was that the phenolic compound, 3,4- dihydroxybenzoic acid, plays a fundamental role in the rooting process of this difficult to root plant. Findings have contributed significantly to greater efficiency in the commercial production of King Proteas
Contact person: Prof ES du Toit.
In an integration of pasture, soil, environmental and weed sciences with an emphasis on environmental problems our Land Reclamation team has developed interesting applications of Coal Ash, an industrial by-product that can cause environmental problems.
The fine coal ash known as fly ash has been used to ameliorate soil and coal discard, by neutralization. Raising the soil or substrate pH in this way inherently creates a better environment for grass roots to develop, thus improving plant production. This helps to optimise post-mining land use, inter alia limiting the amount of heavy metals translocated by the plants or leached out of the newly reclaimed areas or by-product disposal sites.
Preliminary work has indicated that fly ash also has the ability to improve certain microbiological aspects important in soil health and plant production. Coal ash with a coarser texture has been used together with industrial biosolids to create a growth medium where various sub-tropical grasses and trees have been established in an effort to stabilize the surface of industrial by-product disposal sites. The approach it is anticipated will ultimately also use vegetation to curtail the movement of water through these disposal sites.
In related work, waste dumpsites, which contain large amounts of wood ash from campfires, were found to be invaded by certain invasive plant species. Indigenous grass species have now been identified that are adapted to the changed conditions.
They can be used to revegetate such sites, which increasingly occur in wildlife conservation areas. These findings were presented in various papers at the International Coal Ash Conference hosted by the South African Coal Ash Association last year
Contact person: Mr WF Truter.
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