Wednesday, December 1, 2010

Disa draconis - conservation begins at home

I spend my time driving to work in the morning thinking about various issues that pop into my head. Recently, one of these issues has been the plight of some of our South African terrestrial orchid species (geophytes). I has recently read a conservation update on the state of the remaining population of Disa barbata and I was pleased to read that some seedlings that had been reared in vitro with the help of Hildegard Crous had been made available to some specialist Disa growers. I have always believed that private collections have an inicredibly important role to play in the support of species preservation. Disa barbata is maybe just the tip of the ice berg and I wonder how many other currently endangered and threatened local species will also end up one day known only from a single population in a single locality? If we consider the impact of urban sprawl on natural habitat and the invasion of alien trees and other flora and fauna, how long will it be before we are faced with a similar situation with many other species? One of these species could possibly be Disa draconis which was once thought to be common until separated into three species; D. draconis, D. harveiana and D. karooica in 1995 by Johnson and Linder (Johnson, S.D., & Linder, H.P. (1995). Systematics and evolution of the Disa draconis complex (Orchidaceae). Botanical Journal of the Linnean Society, 118: 289-307). The authors mentioned that D. draconis is now restricted to only a few highly threatened populations on the West coast. Since this article was published 15 years have passed...

In an e-mail to Hildegard I mentioned to her that I had germinated D. thodei, D. uniflora and D. atricapilla and I was curious as to the in vitro requirements of D. draconis for which I had some seeds. She replied that the medium used for D. atricapilla would probably be the one to try for D. draconis seed germination so last night I sowed some D. draconis seeds on this as well as dual-phase Disa media. I was also curious to see if the seeds were viable and if they had embryos. I estimate the seeds to have about 70-80% embryos. Attached bellow is a photomicrograph of one of these seeds.

So, now we wait and see if this little experiment will work. It will be a good investment of time and I hope to report positive findings along the way over the next few years.

Disa draconis seed with embryo

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