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Megagametogenesis and embryology of the pecan (Carya illinoensis)
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: T.K. Haulik --- , Republic of South Africa L.C. Holtzhausen --- Department of Horticultural Science, Republic of South AfricaA timetable is presented for megasporogenesis, megagametogenesis, embryo and endosperm development of the pecan [Carya illinoensis (Wang.) K.Koch] under Transvaal Middleveld conditions. Differences between seasons and cultivars were minimal. The fertilized endosperm nucleus was observed about 5 to 7 days... -
Somatic embryogenesis of groundnut (Arachis hypogaea L.): A comparison of four South African genotypes
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: C. M.S. Mienie --- , Republic of South Africa R.E. Terblanche --- , Republic of South AfricaGenetic engineering is an important tool which can be used together with conventional breeding methods in transferring certain economically important traits into cultivated varieties of almost any crop species. One of the methods for gene transfer is the particle bombardment... -
Attempts to obtain Huanglongbing resistant or tolerant sweet orange by embryo rescue from healthy chimeras of diseased citrus fruit
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: S.P. Van Vuuren --- , South Africa B.Q. Manicom --- , South AfricaHuanglongbing remains a threat in the cooler citrus production areas of South Africa despite restrictions on the movement of citrus material from infected areas, cultural control measures, planting of healthy certified trees and the eradication of infected material. The ultimate... -
Early post-cleavage stages and abnormalities identified in the embryonic development of chokka squid eggs Loligo vulgaris reynaudii
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: A. Oosthuizen M. J. Roberts W. H. H. SauerSix early, post-cleavage embryonic stages for chokka squid Loligo vulgaris reynaudii eggs that were developed in an aquarium are identified and described, expanding the embryonic stages for this species from 14 to 20. The influence of water temperature on embryonic... -
POPULATION DYNAMICS AND DEMOGRAPHY OF AN ESTUARINE COPEPOD (PSEUDODIAPTOMUS EESSEI) IN LAKE SIBAYA, A SUBTROPICAL FRESHWATER COASTAL LAKE
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: RC Hart --- , South AfricaPopulation size and stage structure of Pseudodiaptomus hessei (Mrázek) was studied over 27 months at a single site in subtropical Lake Sibaya. Population density varied seasonally from about 1 to 4 individuals per litre, but a fairly stable population structure... -
Sublethal effects of carbaryl on embryonic and gonadal developments of zebrafish Danio rerio
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: PK Mensah --- Department of Zoology, South Africa GH Okuthe --- Department of Zoology, South Africa M Onani --- Department of Chemistry, South AfricaCarbaryl is a broad-spectrum insecticide used to control insect pests. In aquatic environments, it can disrupt the endocrine system and adversely affect the reproductive function of aquatic animals. This study investigated sublethal impacts of carbaryl on embryos and gonads of... -
Sharks caught in the protective gill nets off KwaZulu-Natal, South Africa. 10. The dusky shark Carcharhinus obscurus (Lesueur 1818)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: SFJ Dudley G Cliff MP Zungu MJ SmaleBetween 1978 and 1999, a total of 5 626 dusky sharks Carcharhinus obscurus, constituting 20% of the total shark catch, was caught in the protective nets off KwaZulu-Natal, South Africa. The mean annual catch was 256 sharks (SD = 107.5,... -
Sharks caught in the protective gill nets off KwaZulu-Natal, South Africa. 11. The scalloped hammerhead shark Sphyrna lewini (Griffith and Smith)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: P de Bruyn SFJ Dudley G Cliff MJ SmaleBetween 1978 and 1998, a total of 3 385 scalloped hammerhead sharks Sphyrna lewini was caught in the protective nets off KwaZulu-Natal. The mean annual catch was 166 sharks (range 60–279). There was a significant decrease in catch rate with... -
Sharks caught in the protective gill nets off KwaZulu-Natal, South Africa. 12. The African angel shark Squatina africana (Regan)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: RL Shelmerdine G CliffBetween 1980 and 2001, a total of 661 African angel sharks Squatina africana was caught in the protective nets off KwaZulu-Natal, South Africa. The mean annual catch was 30 sharks (range = 11–69, SD = 12.4), with no trend in... -
Establisbment of embryogenic suspension cultures of Pinus radiata Don.
Item type: Journal Article • Journal: The Southern African Forestry Journal • Authors: A. Jacoby --- Department of Plant Sciences (Botany and Genetics), South Africa A.J. van der Westhuizen --- Department of Plant Sciences (Botany and Genetics), South Africa A-M. Botha --- Department of Genetics/Forest and Agricultural Biotechnology Institute, South AfricaThe development of embryonal suspensor mass (ESM) from immature embryos of Pinus radiata on a solidified growth medium containing 0,5 mgl−1 benzyladenine, 3,0 mgl−1 2,4-dichlorophenoxyacetic acid, 500 mgl−1 casein hydrolysate and 250 mgl-1 L-glutamine was used as inoculum to establish... -
Plant regeneration by somatic embryogenesis in Eucalyptus spp.: current status and future perspectives
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Glória Pinto --- Department of Biology and Centre for Environmental and Marine Studies (CESAM), Portugal Clara Araújo --- Altri Florestal SA, Portugal Conceição Santos --- Department of Biology and Centre for Environmental and Marine Studies (CESAM), Portugal Lucinda Neves --- Altri Florestal SA, PortugalForest tree improvement programs benefit from the emergence of new biotechnological strategies that complement plant developmental biology and discovery of genes associated with complex multigenic traits. Recently, significant progress has been made in the area of plant regeneration via somatic... -
Comparative embryogenesis of Australian and South African viviparous clinid fishes (Blennioidei, Teleostei)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: L Fishelson --- Department of Zoology, George S Wise Faculty of Life Sciences, Israel O Gon --- , South AfricaThe study follows the embryogenesis of 16 species of viviparous clinid fishes (Clinidae, Teleostei), from the Cape south coast of South Africa and from Australia, with comparative remarks on the development of juveniles in oviparous species. The sperm intromitted into... -
Bone growth patterns in two cordylid lizards, Cordylus cataphractus and Pseudocordylus capensis
Item type: Journal Article • Journal: African Zoology • Authors: Amanda J. Curtin --- Department of Zoology, South Africa P. le --- Department of Zoology, South Africa Fras N. Mouton --- Department of Zoology, South Africa Anusuya Chinsamy --- Department of Zoology, South AfricaCross-sections through the midshaft of the femora from an ontogenetic range of individuals were examined for Cordylus cataphractus, a heavily armoured, group-living lizard found in the western parts of South Africa, and Pseudocordylus capensis, an agile, montane lizard, occurring in... -
Ovarian activity and early embryonic development in the rusty bat, Pipistrellus rusticus
Item type: Journal Article • Journal: African Zoology • Authors: M. van der Merwe --- Mammal Research Institute, Department of Zoology and Entomology, South Africa T. Mostert --- Mammal Research Institute, Department of Zoology and Entomology, South AfricaThe reproductive pattern of the female rusty bat, Pipistrellus rusticus, was investigated by means of a histological examination of the ovarian follicles as well as early embryonic development. Bats were collected from two localities in Limpopo Province. Female rusty bats... -
Abundance and activity patterns of the Cape parrot (Poicephalus robustus) in two afromontane forests in South Africa
Item type: Journal Article • Journal: African Zoology • Authors: J.O. Wirminghaus --- School of Botany & Zoology, University of Natal, South Africa Colleen T. Downs --- School of Botany & Zoology, University of Natal, South Africa M.R. Perrin --- School of Botany & Zoology, University of Natal, South Africa C.T. Symes --- School of Botany & Zoology, University of Natal, South AfricaBehaviour, movements and numbers of the rare Cape parrot (Poicephalus robustus) were investigated at two study sites to assess its conservation status and as the basis for an action plan for their conservation. Birds flew regularly to and from nearby... -
Using synergistic exogenous phytohormones to enhance somatic embryogenesis from leaf explants of a Eucalyptus grandis clone
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Muhammad Nakhooda --- Department of Biotechnology and Consumer Sciences, South Africa Eshani Mandiri --- School of Life Sciences, South AfricaSomatic embryogenesis (SE) in Eucalyptus spp. has been limited to germinated seeds, flowers, lignotubers or zygotic embryos. The low yield of somatic embryos from leaf explants has hampered progress, even though leaves offer a more viable source of clonal explants... -
A comparison of calcium and phosphorus in components of fertile and size-matched unbanded Nile crocodile eggs
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: GJ Brown --- University of Pretoria, South Africa PBC Forbes --- University of Pretoria, South Africa JG Myburgh --- University of Pretoria, South Africa JO Nöthling --- University of Pretoria, South AfricaResearch in other species suggests that the source of embryonic calcium (Ca) and phosphorus (P) for Crocodylus niloticus is likely yolk and shell. Using inductively coupled plasma optical emission spectroscopy (ICP-OES), the Ca and P concentration and content of 30... -
Effect of temperature on embryonic development and offspring performance of the African river prawn, Macrobrachium vollenhovenii
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: Judith G Makombu --- University of Buea, Cameroon Cynthia A Bih --- University of Buea, Cameroon Geneva O Nkongho --- Institute of Agricultural Research for Development (IRAD), Cameroon Pius M Oben --- University of Buea, Cameroon Rollins N Ndi --- University of Buea, Cameroon Clovis N Chombe --- University of Buea, Cameroon Mercy B Verkijika --- University of Buea, Cameroon Gerry K Sonkeng --- Aquaculture Tropicale (Aqua-Tropic), Cameroon Tekou Guegang --- University of Dschang, Cameroon Janet H Brown --- Institute of Aquaculture, University of Stirling, United KingdomMacrobrachium vollenhovenii (Herklots, 1857), the largest of the indigenous West African Palaemonidae prawns, has a high potential for aquaculture. This work was carried out to assess the effect of temperature on embryonic development and offspring quality of this species. In...