Studies of nitrogen fixation, nodule structure and nodule mineral distribution in the tribe Psoraleae

Thesis (DTech. degree in Crop Sciences) -- Tshwane University of Technology, 2011.The genus Psoralea (tribe Psoraleae, family Leguminosae) is indigenous to the Cape Fynbos of South Africa and consists of 50 species that occupy different habitats, ranging from well-drained upland soils to creeks and permanent wetlands. However, little is known about their symbiosis, associated microsymbionts and or adaptation to the nutrient-poor, sandy, acidic soils of the Cape Fynbos. This study is the first to report the presence of calcium oxalate crystals in the outer cortex of P. pinnata and the occurrence of alkali and rare earth elements such as Sr, Rb, Zr and Y in tissue components of N2-fixing nodules (with unknown roles/functions)