Plant Growth and Development

Contact: Prof CW Whitehead

The main thrust of research in this field is in the areas of plant biotechnology and postharvest physiology and technology of fresh fruit, vegetables and cut flowers.

Taxonomy, Medicinal Plants and Ethno Botany

Contact: Prof B-E van Wyk

The Department is widely known as a centre of excellence in the field of African medicinal plants, ethno botany and the classification of African plants. One of the main aims of their taxonomic endeavour is to investigate the taxonomic, genetic, chemical and geographical variations in various commercially important indigenous plants, especially those that are potentially useful to the pharmaceutical industry.

Regional patterns of biodiversity and conservation in South Africa: the flora of the Kruger National Park

Contact: Prof M van der Bank

Tree-Bol Africa

Plant Molecular Sys​tematics Laboratory​

A thorough understanding of biodiversity patterns and processes is also required for efficient conservation. Indeed, one of the biggest challenges for conservation biology is to provide conservation planners with ways to prioritise effort. Much attention has been focused on species richness and endemism; however, the conservation of evolutionary process is now acknowledged as a priority in the face of rapid global change. With this research, we are taking a synthetic approach towards explaining the evolution of biodiversity within one of the world’s most renowned protected areas, the Kruger National Park. The scientific goal is to understand how evolutionary history and ecology have shaped biodiversity in the region, and to use this new knowledge to help design science-based conservation actions. Research activities are designed around three complementary disciplines:

  • Molecular Systematics A ‘barcode’ gene that can be used to distinguish between the majority of plant species on Earth has been identified by scientists from UJ and research partners. This gene, which can be used to identify plants using a small sample, could lead to new ways of easily cataloguing different types of plants in species-rich areas like rainforests. It could also lead to accurate methods for identifying plant ingredients in powdered substances, such as in traditional Chinese medicines, and could help to monitor and prevent the illegal transportation of endangered plant species. The team behind the discovery found that DNA sequences of the gene ‘matK’ differ among plant species, but are nearly identical in plants of the same species. This means that the matK gene can provide scientists with an easy way of distinguishing between different plants, even closely related species that may look the same to the human eye. The researchers made this discovery by analysing the DNA from different plant species. They found that when one plant species was closely related to another, differences were usually detected in the matK DNA. Researchers carried out two large-scale field studies: one on the exceptionally diverse species of orchids found in the tropical forests of Costa Rica, and the other on the trees and shrubs of the Kruger National Park in South Africa. This was a collaborative project between teams from South Africa (Dr Michelle van der Bank, Department of Botany and Plant Biotechnology, University of Johannesburg), United Kingdom (Dr Vincent Savolainen, dual appointee at Imperial College London’s Department of Life Sciences and the Royal Botanic Gardens, Kew) and Costa Rica (Diego Bogarin, Lankester Botanical Garden, University of Costa Rica). Using specimens collected from Costa Rica, were able to use the matK gene to identify 1,600 species of orchid. In the course of this work, they discovered that what was previously assumed to be one species of orchid was actually two distinct species that live on different slopes of the mountains and have differently shaped flowers adapted for different pollinating insects. The team was also able to use the matK gene to identify the trees and shrubs of the Kruger National Park, also well known for its big game animals. In the long run the aim is to build on the genetic information the team gathered from Costa Rica and South Africa to create a genetic database of the matK DNA of as many plant species as possible, so that samples can be compared to this database and different species accurately identified.
  • Evolutionary Ecology Research focuses on the following questions: What is the regional pattern of biodiversity; how is biodiversity structured within the various ecoregions (ecozones) of the Kruger National Park, and beyond? How can phylogenetic relationships inform community assembly? Are communities some random assemblages of the regional species pool? Or instead, are communities made of well-adapted taxa in which similar traits have converged independently in separate lineages?
  • Conservation Biology Research focuses on the following questions: What is the geographic distribution of biodiversity as measured by various indices, such as endemism, species richness, or phylogenetic diversity? How are these indices correlated, could one be used as a surrogate for the others? How is extinction risk distributed geographically and with regard to the phylogeny? Are there ecoregions or specific lineages more prone to extinction? Are there traits that increase extinction risks? Are there regions that deserve particular conservation attention due to their exceptional phylogenetic diversity and evolutionary history?