A5049433278- Legume Nitrogen Fixing Symbiosis
- Agronomic Practices and Intercropping Systems
- Agricultural pest management studies
- Soil Carbon and Nitrogen Dynamics
- Ecology and Vegetation Dynamics Studies
- Light effects on plants
- Plant Diversity and Evolution
- Plant nutrient uptake and metabolism
- Botany and Plant Ecology Studies
- Nematode management and characterization studies
- Soybean genetics and cultivation
- Genetic and Environmental Crop Studies
- Plant Water Relations and Carbon Dynamics
- Plant responses to elevated CO2
- Marine and coastal plant biology
- Pasture and Agricultural Systems
- Plant Parasitism and Resistance
- Polar Research and Ecology
- Plant and animal studies
- Seed Germination and Physiology
- Ethnobotanical and Medicinal Plants Studies
- Genomics and Phylogenetic Studies
- Plant Micronutrient Interactions and Effects
- Botanical Research and Chemistry
- African Botany and Ecology Studies
University of Cape Town
2016-2025
Stellenbosch University
2015
Cape Peninsula University of Technology
2004
Rhizobial diversity and host preferences were assessed in 65 native Fynbos legumes of the papilionoid legume tribes Astragaleae, Crotalarieae, Genisteae, Indigofereae, Millettieae, Phaseoleae, Podalyrieae, Psoraleeae Sesbanieae. Sequence analyses chromosomal 16S rRNA, recA, atpD symbiosis-related nodA, nifH genes parallel with immunogold labelling assays identified symbionts as alpha- (Azorhizobium, Bradyrhizobium, Ensifer, Mesorhizobium Rhizobium) beta-rhizobial (Burkholderia) lineages...
Recent findings point to plant root traits as potentially important for shaping the boundaries of biomes and maintaining communities within. We examined two hypotheses: 1) Thin-rooted strategies might be favored in with low soil resources; 2) these may act, along fire, maintain sharp boundary between Fynbos Afrotemperate Forest South Africa. These differ biodiversity, traits, physiognomy, yet exist alternative stable states on same geological substrate climate conditions. conducted a 4-y...
1 Indigenous species of Acacia are common in African savannas that have N-rich soils. This raises doubt regarding the extent plant dependence on N2 -fixation. Why would spp. enjoy an advantage over other tree N-replete soils? 2 We tested hypothesis competition by grass for nutrients induce increased nodulation karroo, A. nilotica, tortilis and nigrescens seedlings enable them to survive better than a non-nodulating congeneric (A. ataxacantha). A glasshouse pot experiment was conducted...
ABSTRACT Rhizobia of the genus Burkholderia have large-scale distribution ranges and are usually associated with South African papilionoid American mimosoid legumes, yet little is known about their genetic structuring at either local or global geographic scales. To understand variation different spatial scales, from individual legumes in fynbos (South Africa) to a context, we analyzed chromosomal (16S rRNA, recA ) symbiosis ( nifH , nodA nodC gene sequences. We showed that diversity...
Abstract Indigofera L. is the most diverse genus in tribe Indigofereae and third largest Fabaceae with over 750 species distributed tropical to temperate areas of world. The centre diversity lies on African continent, accounting for two-thirds its global diversity. Diversification Indigofer a’s four main clades began Early Miocene, Tethyan Cape Clades having slightly older crown ages than Pantropical Paleotropical Clades. Using biogeographical models under a newly assembled, more...
The goal of this work is to study the evolution and degree horizontal gene transfer (HGT) within rhizobial genera both Alphaproteobacteria (Mesorhizobium, Rhizobium) Betaproteobacteria (Burkholderia), originating from South African Fynbos legumes. By using a phylogenetic approach comparing multiple chromosomal symbiosis genes, we revealed conclusive evidence high degrees nodulation genes among closely related species groups rhizobia, but also with distant genetic backgrounds (Rhizobium...
Seventeen herb, shrub and tree species of commercial ecological importance in southern Africa were exposed at one location to ultraviolet-B (UV-B, 280-315 nm) radiation approx. 35 % above clear-sky background (control). The aims assess how UV-B affects canopy area, dry mass, some biochemical morphological properties leaves, investigate whether differences between are related growth form the plants. There was no pattern response form. Leaves trees had altered chlorophyll a b, carotenoid...
The aim of this study was to assess P acquisition efficiency in 5 cowpea genotypes mixed culture and at different plant densities using assays acid alkaline phosphatase activity measurement organs. Five (2 improved cvv. ITH98-46 TVu1509, 3 farmer-selected varieties, namely Bensogla, Sanzie, Omondaw) were grown the field 2 planting (83 333 166 666 plants/ha) under monoculture with sorghum during 2005 2006. Fresh roots rhizosphere soils collected years experimentation, assayed for activity....
A field experiment involving two planting densities (83,333 and 166,666 plants per ha), cropping systems (monoculture mixed culture) five cowpea [Vigna unguiculata L. (Walp.)] genotypes was conducted at Nietvoorbij (33°54S, 18°14E), Stellenbosch, South Africa, to select material with superior growth water-use efficiency (WUE). The results showed significantly higher photosynthetic rates, stomatal conductance transpiration in leaves of low density monoculture due greater chlorophyll (Chl)...
We investigated the physiological basis for tolerance of limiting P supply and enhanced growth with simultaneous addition N in Aspalathus linearis (Burm. f.) R. Dahlgren. It was hypothesised that increasing would stimulate acquisition mechanisms enhance plant high supply. In sand, plants received 100μM, 300μM, 500μM 700µM at a low level 10µM 100µM. solution, 200μM 500µM 5µM 15µM. Cluster roots formed only Roots showed greater citrate malate production phosphatase activity than 15µM P. At P,...
Over 760 legume species occur in the ecologically-heterogeneous Core Cape Subregion (CCR) of South Africa. This study tested whether main symbionts CCR legumes (Burkholderia and Mesorhizobium) are phylogenetically structured by altitude, pH soil types. Rhizobial strains were isolated from field nodules diverse sequenced for 16S ribosomic RNA (rRNA), recombinase A (recA) N-acyltransferase (nodA). Phylogenetic analyses performed using Bayesian maximum likelihood techniques. signals determined...
Vigna unguiculata (L.) Walp. (cowpea), Glycine max Merr (soybean) and Phaseolus vulgaris (common bean) plants were exposed to UV-B radiation at above- below-ambient levels, their effects on growth, symbiotic performance root concentration of metabolites assessed. Moderately highly elevated exposures averaging 32 62% above ambient had no effect plant total dry matter, nodule number, mass, size, N fixed or flavonoids, anthocyanins, soluble sugars starch in the three species studied. However,...
Calobota sericea is a perennial legume species from South Africa that has the potential to be implemented as fodder crop in water-limited agro-ecosystems. Apart dormancy breaking requirements, no information regarding germination and seedling establishment requirements of C. currently available. Therefore, aim this study was determine abilities at different temperatures, water potentials seed burial depths. In first trial seeds were incubated constant temperatures 5–30 °C 5 increments second...
The tribe Psoraleeae (Leguminosae subfamily Papilionoideae) comprises 185 species in nine genera that have a nearly worldwide distribution, occurring predominantly Mediterranean regions. About 60% of the belong to genera, Otholobium C.H.Stirt. and Psoralea L., which centre diversity Cape Floristic Region South Africa. Since previous molecular studies sampled only few from this region, study sought determine phylogenetic position southern African test whether they are monophyletic....