The occurrence of coralloid roots on the South African species of the Cycadales and their ability to fix nitrogen symbiotically

Thirty-three species of Encephalartos, which include all the known species indigenous to the Republic of South Africa, together with Stangeria eriopus, were found to form coralloid roots. In all cases, specimens were found in which the coralloid roots were infected with Cyanobacteria (blue-green algae) and these roots in all cases reduced acetylene to ethylene, and fixed nitrogen. Daar is vasgestel dat al 33 die Encephalartos-spesies wat ondersoek is, sowel as Stangeria eriopus koraalvormige wortels vorm. Die ondersoekte spesies het al die beskrewe spesies wat inheems aan die Republiek van Suid-Afrika is ingesluit. In alle gevalle is eksemplare gevind waarvan die koraalvormige wortels met Cyanobacteria (blougroen alge) geïnfekteer was. Sulke wortels het in alle gevalle oor die vermoë beskik om asetileen tot etileen te reduseer en om stikstof te bind.