The Mutavhatsindi tree is described as “the most wanted medicinal tree” in the Vhembe district and is intensely exploited for its medicinal bark and roots. (Brita Lomba, CC BY-SA 3.0)
Conservationists are in a race against time to save the fast-dwindling “magical” Mutavhatsindi tree, which is only found in the Vhembe District in Limpopo, from extinction.
Within South Africa, the critically endangered species (Brackenridgea zanguebarica), also commonly known as the yellow peeling plane, only exists in a small 110 hectare subpopulation in the Mutavhatsindi Nature Reserve.
It is described as “the most wanted medicinal tree” in the Vhembe district and is intensely exploited for its medicinal bark and roots. Traditional healers use the tree’s yellow dye to treat wounds, worms, aching hands, swollen ankles and amenorrhea.
According to the South African National Biodiversity Institute, traditional medical practitioners believe its roots or bark should only be collected by a nude person at midnight, and that anyone who uproots or retrieves its roots or bark without having undergone the prescribed ritual won’t live past the age of 50.
That no one had been able to successfully propagate the tree to ensure its continued survival raised huge concerns, given its declining population, according to Mpendulo Gabayi, a conservation horticulturist and tree expert at Kirstenbosch National Botanical Garden.
But their efforts are now taking root. Gabayi, together with horticulturalist Mpho Mathalauga, of the KwaZulu-Natal National Botanical Garden, and Ntsakisi Masia, a seed collector from Thohoyandou National Botanical Garden, are celebrating the first successful rooting of the tree.
It was propagated successfully after experimenting with many different propagation methods, Gabayi said. “We have established a number of propagation methods in an attempt to look at which one would work on this species. This included stem, tip, internodal, heel cuttings and air layering. Air layering came out to be the most promising method.”
Their work involved the manipulation of plant growth regulators and using the air layering method, and DynaBall (PBR International), they got positive results. The propagules had shown a good set of healthy roots emerging but had a low rooting percentage of 15%.
“Through a successful procedure of air layering, new trees can be grown from branches that are still attached to the parent plant. More propagation methods and procedures are still being trialled to build onto the current successful experiment.”
The project is being run by Kirstenbosch, the Missouri Botanical Garden in the United States, and the University of Venda. It is supported by ArbNet, Botanic Gardens Conservation International, the Millenium Seed Bank Partnership and Propagation BioScience Research International. They have teamed up to create a long-term project that will eventually result in saving and preserving the South African gene pool, through ex situ (conservation outside its natural habitat) and in situ conservation.
Experts estimate the local population may be lost entirely within the next 15 years. The current rate of decline is not precisely known, but between 1990 and 1997 the local population shrunk by 86%, from 140 trees per hectare to just 25 trees per hectare.
Ex situ conservation measures are critical to preserving existing genetic diversity in the Limpopo population, Gabayi explained. “While there have been several studies on its propagation, it remains a challenge to propagate it both sexually and asexually. Difficulties include a hard seed coat, deep physical dormancy, and seed parasitism.”
As part of their work, and through the assistance of the Millennium Seed Bank Partnership, Gabayi and his colleagues hand-pollinated the tree’s flowers using a small paintbrush.
“This is a manual transfer of pollen from the anther or male organ to the stigma or female organ of the flower for the purpose of increasing fertilisation,” Gabayi said.
He said the team had made every effort to prevent potential seed parasitism and that the seeds were collected in good condition. Genetically representative samples of DNA were taken from the trees, and all the existing trees mapped in the maternal line.
This documented information is being stored in Missouri, alongside the genetic material, for future studies.
In December 2020, they returned to Limpopo to harvest the Mutavhatsindi seeds they pollinated by hand and started the process of propagation.
“The ability to reliably propagate the species would inform ex situ efforts as well as reintroduction efforts, if in situ protections can be increased in the future, or if the existing reserve is expanded. Cultivation could also play a role in future efforts to reduce demand on wild populations for traditional medicine.”
Bark harvest for traditional medicine causes high mortality in larger, reproductive trees, and consequently the Limpopo population shows signs of low fruit production and poor seedling recruitment, Gabayi said, adding: “High demand in local herbal medicine markets and compounding threats related to grazing, wood collection, and agriculture will remain significant challenges without swift measures to reduce overharvesting.”
The overall success of this project contributes to the Global Strategy for Plant Conservation; making 20% of threatened plant species available for recovery programmes, and at least 75% available in the country of origin. The strategy seeks to halt the continuing loss of plant diversity, noting how, “without plants, there is no life” and that the planet’s functioning and human survival depends upon plants.
Threatened plant species have the potential to become extinct. “Future generations may not be able to experience some of these species [and] the cascading extinction of other organisms that depend on them may lead to ecological damage. By prioritising plants such as Mutavhatsindi for conservation, a great loss of traditional medicine may not be experienced in future.”
There is great potential for mass production of the species “now that we have managed to break code on the vegetative propagation,” he said. This could have it readily available for locals, easing pressure on the wild population. “Saplings of these trees will be kept in the botanical gardens and particularly in Thohoyandou Botanical Gardens and kept as backup collection of the wild population.”
Further propagation techniques and methods will be explored while focusing on air layering to increase rooting percentage. “The main objective is to have the species in production and community engagement. There is a need for collaboration with traditional leaders, tribal authorities, traditional healers and local communities to conserve ‘Mutavhatsindi’ with the aim of developing sustainable use of this tree.”
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