In vitro technology for propagation of critically endangered Euphorbia species
The present invention relates to the development of an in vitro culture technology for multiplication of Euphorbia groenewaldii R.A. Dyer and Euphorbia clivicola R.A. Dyer, which are indigenous to South Africa and occur in only a few localities in Limpopo Province. The plants are classified as “Critically Endangered” in the Red List of South African Plants due to threats by urban and industrial developments, severe overgrazing and illegal harvesting for horticultural, trading and medicinal purposes. In vivo propagation of these plants, by seeds and vegetatively, is very limited due to the unavailability of plant material, slow growth and low multiplication rate. The in vitro culture of such succulent plants is also problematic due to the presence of toxic latex, lethal oxidative browning, susceptibility of soft stem tissues to rotting and high mortality of plants. However, the newly developed in vitro technology provides a complete protocol for shoot multiplication, rooting and acclimatisation of plantlets under controlled environmental conditions. Hardening off of regenerated plants in a greenhouse was also successfully achieved. The technology has commercial potential for mass production of these and other economically valuable succulent plants that are rare and difficult to propagate, without posing a threat to the extinction of the natural plant populations, while meeting the people’s needs and contributing to the local economy. Indigenous nurseries, traders and private collectors of succulent plants would be interested to buy such plants for horticultural purposes and ex situ conservation of rare plant species.