Search
Search results for
We found
18 results for you
-
Influence of sowing depth on the germination of Karoo shrubs and grasses
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: S.A. Barnard --- Department of Agriculture and Water Supply,Knowledge of the germination behaviour of desirable plants to be sown in the veld for veld improvement is still inadequate. To gain this knowledge, seed of different species of Karoo bushes and grasses were planted on two soil types at... -
The influence of tree thinning on the establishment of herbaceous plants in a semi-arid savanna of southern Africa
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: G.N. Smit F.G. RethmanThe investigation was conducted on an area covered by a dense stand of Colophospermum mopane. Seven plots (65 m × 180 m) were subjected to different intensities of tree thinning, ranging from a totaly cleared plot (0%) to plots thinned... -
Histological studies to evaluate gonad development in Barbus neefi (Cyprinidae), the sidespot barb, from South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: W VlokBarbus neefi gonads were collected seasonally from specimens from the Selati and Makutsi Rivers, tributaries of the Olifants River in Limpopo and Mpumalanga provinces, South Africa, preserved in 4% formalin solution and stained with hematoxilin/eosin. These collections represent new records... -
Differentiated gonochorism in Nile perch Lates niloticus from Lake Victoria, Uganda
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: RK Basiita --- , Uganda C Aruho --- , Uganda D Kahwa --- , Uganda E Nyatia --- , Uganda FW Bugenyi --- Department of Zoology, Uganda J Rutaisire --- , UgandaGonadal development and structure were examined in 317 Nile perch, Lates niloticus, of 4 to 157 cm SL taken from Lake Victoria, Uganda, in 2005–2006. Macroscopic and histological investigation showed a differentiated gonochoristic pattern, with no juvenile intersexuality. Oogonial cells... -
Effects of light intensity on cylindrospermopsin production in the cyanobacterial HAB species Cylindrospermopsis raciborskii
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: J Dyble PA Tester RW LitakerThe role of light intensity on growth and the production of the hepatotoxin cylindrospermopsin (CYN) in the cyanobacterial harmful algal bloom species Cylindrospermopsis raciborskii was investigated using cultured isolates grown in N-free media under a series of neutral density screens... -
Seedling recruitment of Colophospermum mopane on the Highveld of Zimbabwe
Item type: Journal Article • Journal: The Southern African Forestry Journal • Authors: D. Mlambo --- Department of Forest Resources and Wildlife Management, Zimbabwe P. Nyathi --- Department of Forest Resources and Wildlife Management, ZimbabweFactors controlling seedling recruitment of Colophospermum mopane (Kirk ex. Benth) Kirk ex. J. Leonard were investigated on the high veld of Zimbabwe. Seed germination and seedling survival and growth were monitored under canopy and outside canopy microhabitats for a period... -
Cylindrospermopsis raciborskii, a toxic invasive cyanobacterium in South African fresh waters
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: Sanet Janse van Vuuren GP KrielCylindrospermopsis raciborskii, a problem-causing cyanobacterium capable of releasing potent toxins, has become increasingly prevalent in South African freshwaters, especially in the lower reaches of the Orange River. This organism was first detected during the summer (January to March) of 2000... -
Reproduction in the viviparous South African clinid fish Fucomimus mus
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: HG MoserDescription of the reproductive anatomy, histology and seasonality of reproduction of the viviparous clinid fish, Fucomimus mus, was based on a collection of 227 specimens from various intertidal localities off the south-east coast of South Africa. Males produce sperm throughout... -
Reproductive system and the spermatophoric reaction of the mesopelagic squid Octopoteuthis sicula (Rüppell 1844) (Cephalopoda: Octopoteuthidae) from southern African waters
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: HJT Hoving MR Lipiński JJ VidelerReproductive features of the poorly known oceanic squid Octopoteuthis sicula are described and quantified to gain insight into the reproductive biology of the species. The data are based on 39 complete and partial specimens from southern African waters, collected between... -
Radiation exposure exerts its adverse effects on sperm maturation through estrogen-induced hypothalamohypophyseal axis inhibition in rats
Item type: Journal Article • Journal: African Zoology • Authors: M.J. Makinta --- Physiology Department, South Africa J.M. Brinders --- Manufacturing and Material Division, South Africa K.A. Smith --- Physiology Department, South AfricaIrradiation has adverse effects on reproductive aspects such as spermatogenic cell population and cell malformation, leading to reduced sperm count and non-viable spermatozoa. This has overshadowed possible effects of radiation exposure on biochemical environment throughout the epididymis and the viability... -
Ultrastructure of epididymal spermatozoa in three social African mole-rats of the genus Cryptomys (Rodentia: Bathyergidae): conservatism in sperm morphology
Item type: Journal Article • Journal: African Zoology • Authors: K.A. Maswanganye --- Mammal Research Institute, Department of Zoology and Entomology, South Africa G.P. Malherbe --- Mammal Research Institute, Department of Zoology and Entomology, South Africa N.C. Bennett --- Mammal Research Institute, Department of Zoology and Entomology, South AfricaThe morphology, size and three-dimensional structure of spermatozoa from three representatives of the genus Cryptomys were investigated. To date, there has been no study to either elucidate the morphological features or relative dimensions of spermatozoa in the genus Cryptomys specifically,... -
Maturity, spermatogenesis and seasonal reproductive cycle of male Rhinobatos annulatus (Muller & Henle, 1841) from Algoa Bay, South Africa, and a novel description for sperm release from the spermatocyst
Item type: Journal Article • Journal: African Zoology • Authors: G.J. Rossouw --- Department of Zoology, South AfricaDespite the unique gonadal organization and reproductive strategies known for elasmobranchs very little is known about the reproductive biology of local species. The stages of spermatogenesis for the lesser guitar fish, Rhinobatus annulatus, has not been described and specifically the... -
Structure and cytology of the testes of Labeo victorianus (Pisces: Cyprinidae)
Item type: Journal Article • Journal: African Zoology • Authors: Justus Rutaisire --- Department of Wildlife and Animal Resources Management, Uganda Ruth T. Muwazi --- Department of Wildlife and Animal Resources Management, Uganda Anthony J. Booth --- Department of Ichthyology and Fisheries Science, South AfricaTestes macromorphology and histomorphology together with sperm cytology are described for a potamodrometic cyprinid fish, Labeo victorianus, from Lake Victoria. Testes were found to be paired and elongate, suspended by a mesorchium on either side of the swim bladder. A... -
Describing gonad development and gametogenesis in southern Africa’s endemic box jellyfish Carybdea branchi (Cubozoa, Carybdeidae)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: R Mohamed --- Department of Biodiversity and Conservation Biology, South Africa H Skrypzeck --- Department of Biodiversity and Conservation Biology, South Africa MJ Gibbons --- Department of Biodiversity and Conservation Biology, South AfricaInformation on the reproductive development of species of box jellyfish (class Cubozoa) is poor globally, despite their significance as potent stingers and worrying projections about range expansions. While most species are confined to tropical and subtropical waters, the South African... -
Spermatozoa morphology and ultrastructure in Nile perch, Lates niloticus (Linnaeus, 1758)
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: D Kahwa --- Department of Wildlife and Aquatic Resources, Uganda E Nyatia --- Department of Biotechnical and Diagnostic Services, Uganda J Rutaisire --- Aquaculture Research and Development Centre, Uganda H Kaiser --- Department of Ichthyology and Fisheries Science, South AfricaLates niloticus is a valuable commercial fish species with good potential for aquaculture. However, there is limited information on the type and structure of the Nile perch spermatozoon, which could potentially aid in culture of this species. Here, we describe... -
Assessment of laryngeal muscle and testicular cell types in Xenopus laevis (Anura Pipidae) inhabiting maize and non‐maize growing areas of South Africa
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: ErnestE. Smith --- Texas Tech University, LouisH. Du Preez --- North‐West University, South Africa Angella Gentles --- Texas Tech University, KeithR. Solomon --- University of Guelph, Canada Bernard Tandler --- Case Reserve University, JamesA. Carr --- Texas Tech University, GlenL. Van Der Kraak --- University of Guelph, Canada RonaldJ. Kendall --- Texas Tech University, JohnP. Giesy --- Michigan State University, TimothyS. Gross --- Florida Caribbean Science Center‐USGS‐BRD,We tested the hypothesis that adult African clawed frogs (Xenopus laevis) inhabiting water bodies in maize‐growing areas (MGA) of South Africa would exhibit differences in testicular structure compared to frogs from water bodies in non‐maize‐growing areas (NMGA) in the same... -
Premature sperm ejaculation in captive African brown house snake Lamprophis fuliginosus
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: AnthonyJ. Wilmes --- Saint Louis University, USA DustinS. Siegel --- Saint Louis University, USA RobertD. Aldridge --- Saint Louis University, USAMany ophidians exhibit prolonged copulation, a behaviour hypothesised to be the result of a slow and gradual ejaculation process or a behaviour aimed toward reducing sperm competition (male mate guarding). While observing courtship behaviour in a captive colony of the... -
Life-history traits of the false jacopever Sebastes capensis (Scorpaenidae: Sebastinae) in South African waters
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: T Mohamed --- Department of Biological Sciences, University of Cape Town, South Africa CG Attwood --- Department of Biological Sciences, University of Cape Town, South AfricaThe genus Sebastes (rockfishes) of family Scorpaenidae (scorpionfishes) contains over 110 species, of which the false jacopever Sebastes capensis is the only one found in South African waters. Although it is a commonly caught linefish along the west coast of...