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A complex dormancy mechanism in seeds of the weed Rubus cuneifolius
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: J. van Staden --- Department of Botany, PetaL. Campbell --- ,Both the endocarp and embryo contribute to the dormancy of Rubus cuneifolius seed. Whereas scarification was found to break the dormancy imposed by the endocarp, embryo dormancy could only be overcome by a combination of treatments. These treatments consisted of... -
Scarification and stratification of Combretum erythrophyllum (Burchell) seed and fruit for uniformity in germination
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: P. Wickens --- Applied Natural Sciences, Republic of South Africa W.G. Gaum --- Applied Natural Sciences, Republic of South AfricaDifferent scarification and stratification processes were used to soften River Bushwillow or Combretum etythrophyllun (Burchell) fruit and seed coverings and to determine the percentage, rate and uniformity of germination. Treatments included stratification, hot water scarification, leaching in cold water, soaking... -
THE SUMMER CONDITION OF THREE EASTERN TRANSVAAL RESERVOIRS AND SOME CONSIDERATIONS REGARDING THE ASSESSMENT OF TROPHIC STATUS
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: R.D. Walmsley --- , South Africa D.F. Toerien --- , South AfricaSummer temperature, oxygen and light penetration profiles in the Da Gama, Klipkopje and Witklip Reservoirs are presented. Analysis of waters from different depths showed the presence of chemical stratification despite the absence of clear thermal stratification. An algal bioassay procedure... -
THE LIMNOLOGY OF SOME SOUTH AFRICAN IMPOUNDMENTS I. THE PHYSICO-CHEMICAL LIMNOLOGY OF HARTBEESPOORT DAM
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: W.E. Scott --- , South Africa M.T. Seaman --- , South Africa A.D. Connell --- , South Africa S.I. Kohlmeyer --- , South Africa D.F. Toerien --- , South AfricaHartbeespoort Dam is a eutrophic, warm monomictic lake with overturn occurring in April. The lake is stratified for about six months of the year and in late summer the stratification appears stable. Light penetration in the dam depends both on... -
A PRELIMINARY LIMNOLOGICAL STUDY OF BUFFELSPOORT DAM AND ITS CATCHMENT
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: R.D. Walmsley --- , D.F. Toerien --- ,A limnological survey of the Buffelspoort Dam and its catchment between 1973 and 1975 showed that the water of the area contained extremely low concentrations of dissolved minerals and that there was no point source of nutrient supply to the... -
LIMNOLOGICAL MODELLING: SIMULATION OF VERTICAL PROFILES OF TEMPERATURE, DISSOLVED OXYGEN AND NUTRIENTS. I. THEORY
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: B. Henderson-Sellers --- Department of Civil Engineering, United KingdomIn a body of water, variations occur in all limnological parameters on many time and space scales. Modelling can either be specific - for a selected subset; or can attempt to simulate the gross characteristics of e.g. current, temperature, algal... -
A NOTE ON SALINITY AND OXYGEN STRATIFICATION IN THE MARINA DA GAMA, ZANDVLEI
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: B.R. Davies --- Zoology Department, Republic of South Africa B.A. Stewart --- Zoology Department, Republic of South AfricaTen months data (March to December, 1983), on temperature, salinity and dissolved oxygen are reported for two canals within the Marina Da Gama, Zandvlei, a coastal lake periodically open to the sea. They show that although there was minimal temperature... -
The Evolution of Thermohaline Structure in a Closed Estuary
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: J.H. Slinger --- , South Africa J.L. Largier --- , U.S.A.Following the closure of the mouth of the Palmiet estuary in February 1988, the thermohaline structure was recorded at approximate weekly intervals. The evolution of the two-layer structure was studied and the mixing processes causing the changes were determined. Vertical... -
Topographical units and soil types prove more efficient for vegetation sample site placement than Land Type units in semi-arid savanna, North West province, South Africa
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Francois Viljoen --- Department of Nature Conservation, South Africa Kerryn Bullock --- Department of Nature Conservation, South Africa Mike Panagos --- Department of Nature Conservation, South Africa Willem Myburgh --- Department of Nature Conservation, South AfricaLand Type mapping units were used to stratify the Heritage Park corridor, in the North West province, South Africa, into eight Land Type units prior to placing 109 floristic sample sites. At each site, species composition and relative frequency data... -
Dynamics of a cyanobacterial bloom in a hypereutrophic reservoir, Lake Chivero, Zimbabwe
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: L Mhlanga --- Department of Biological Sciences, Zimbabwe W Mhlanga --- Department of Environmental Science, ZimbabweBlooming and non-blooming periods between 2004 and 2006 in a hypereutrophic reservoir, where cyanobacterial blooms have previously been reported to be permanent, presented an opportunity to characterise factors that may favour cyanobacterial dominance. As a bloom developed in May 2004,... -
The Effect of Long Term Stratification on the Germination of Pinus Pinaster Ait
Item type: Journal Article • Journal: South African Forestry Journal • Authors: D. G.M. Donald --- ,Trials to determine the effect of long term stratification on Pinus pinaster seed subjected to periods of room temperature storage following cold storage and cold storage only indicated that the former could reduce viability of the seedlots. Dormancy of all... -
A bloom of Dinophysis acuta in a thin layer off North-West Portugal
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MT Moita L Sobrinho-Gonçalves PB Oliveira S Palma M FalcãoDinophysis acuta, which is responsible for diarrhetic shellfish poisoning, reached particularly high concentrations on the north-west coast of Portugal in 2003. In the Ría de Aveiro (40°41'N), the species reached a maximum concentration of 5.0 × 104 cells l−1 on... -
Are different species of Dinophysis selected by climatological conditions?
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: L Escalera B Reguera Y Pazos A Moroño JM CabanasDinophysis acuminata and D. acuta, the main agents of diarrhetic shellfish poisoning outbreaks in the Galician Rías Baixas, North-West Spain, appear segregated in time and/or space and exhibit considerable interannual variability. To explore the specific requirements of the two species... -
Dusky dolphins Lagenorhynchus obscurus and Cape fur seals Arctocephalus pusillus pusillus: fatty acid composition of their blubber and prey species
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: O Grahl-Nielsen --- Department of Chemistry, Norway J-O Krakstad --- , Norway L Nøttestad --- , Norway BE Axelsen --- , NorwayThe fatty acid composition of the blubber of five dusky dolphins Lagenorhynchus obscurus and five Cape fur seals Arctocephalus pusillus pusillus from the northern Benguela ecosystem (South-East Atlantic) and their main prey was determined. Differences in fatty acid composition of... -
Climate change impact on the limnology of Lake Kariba, Zambia–Zimbabwe
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: TS Mahere --- Department of Biological Sciences, Zimbabwe MZ Mtsambiwa --- University of Zimbabwe Lake Kariba Research Station, Zimbabwe PC Chifamba --- Department of Biological Sciences, Zimbabwe T Nhiwatiwa --- Department of Biological Sciences, ZimbabweThere is evidence that global warming is changing the thermal regimes of tropical lakes and this paper examines the impact of warming on the limnology of Lake Kariba. Between 1986 and 2011 the mean temperature of the lake rose by... -
Preventative foot care in people with diabetes: Quality patient education
Item type: Journal Article • Journal: Journal of Endocrinology, Metabolism and Diabetes of South Africa • Authors: Janse G van Rensburg --- Centre for Diabetes and Endocrinology,Foot ulceration and amputation cause extensive burden on individuals and health care systems. One of the reasons for the poor outcome of foot complications in developing countries is the lack of patient education. Due to the multi-factorial pathology of diabetic... -
On construction of index funds in South Africa
Item type: Journal Article • Journal: South African Journal of Accounting Research • Authors: D J Bradfield --- Department of Statistical Sciences, C S Ardington --- Department of Statistical Sciences,Index funds, an increasingly popular form of investment in the US and UK since the 1970s, have recently emerged in South Africa. This paper examines two methods of constructing index funds in the South African environment. These two methods, namely... -
Prostate cancer profile and risk stratification of patients treated at Universitas Annex Department of Oncology, Bloemfontein, Free State, during 2008 to 2010
Item type: Journal Article • Journal: South African Family Practice • Authors: A Sherriff --- Department of Oncology, South Africa N Da Costa --- Faculty of Health Sciences, School of Medicine, South Africa A Engelbrecht --- Faculty of Health Sciences, School of Medicine, South Africa A Li --- Faculty of Health Sciences, School of Medicine, South Africa N Price --- Faculty of Health Sciences, School of Medicine, South Africa G Joubert --- Faculty of Health Science, Department of Biostatistics, South AfricaBackground: Prostate cancer commonly occurs in older men. Since TNM staging excludes prostate-specific antigen (PSA) level and Gleason score, patients with prostate cancer are divided into risk groups when deciding on treatment options. This study determined the profile and risk... -
Seasonal cycle of the salinity barrier layer revealed in the northeastern Gulf of Guinea
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: AN Dossa --- International Chair in Mathematical Physics and Applications (ICPMA-UNESCO Chair), Benin CY Da-Allada --- International Chair in Mathematical Physics and Applications (ICPMA-UNESCO Chair), Benin G Herbert --- Institut de Recherche pour le Développement (IRD), Instrumentation, Moyens Analytiques, France B Bourlès --- Institut de Recherche pour le Développement (IRD), Instrumentation, Moyens Analytiques, FranceThe region located in the far northeast of the Gulf of Guinea (NEGG), eastern tropical Atlantic, remains poorly documented due to a lack of available in situ ocean data. Heavy rainfall and intense river discharges observed in this region induce... -
Effects of form, fineness and placement of lime with and without soil tillage on barley and canola growth and development
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: JR van der Nest --- , South Africa AG Hardie --- , South Africa J Labuschagne --- , South Africa PA Swanepoel --- , South AfricaNo-tillage systems and slow movement of surface-applied limestone can lead to stratification of soil acidity. Incorporation of lime by tilling soil is not preferred by producers following conservation agriculture practices. There is limited research on ways to facilitate lime movement...