Africa Stock Research Articles

Survival and growth of seedlings of 14 Australian dry-zone Acacias under nursery conditions in Zomba, Malawi

Results are presented of a nursery study on survival growth and biomass production of 14 Australian dry-zone Acacia species in Zomba. The seeds of the species were sown directly in polythene tubes after being pretreated with boiling water. Survival, height and diameter assessments were taken at 1, 2 and 3 months after a 30-day germination period in the nursery. Once germinated, the ability of the seedlings to survive is very high. However, the species are susceptible to fungal attack (powder mildew) while in the nursery which, depending on the species and level of attack can reduce both survival and growth of the seedlings. Investigations on Control measures of the fungal attack are in progress. The study has shown that A. gonoclada, A. mangium, A. shirley and A. bidwillii are slow-growing in the nursery. On the basis of heigtht growth alone, these will require more than 3 months in the nursery to attain the current recommended 20-cm height for field-planting of nursery stock in southern Africa. Acacias adsurgens, A. auriculiformis, A. aulacocarp, A. monticola, A. polystachya and A. difficilis on the other hand showed fast growth in the nursery and a period of 2–3 months in the nursery would be sufficient to achieve good-quality planting stock. The rest of the species would require a minimum of 3 months in the nursery, although not necessarily as much as 4 months.

Studies on the constituents of Asclepiadaceae plants. LXII. The structures of two glycosides, cynafoside-A and -B, with a novel sugar chain containing a pair of optically isomeric sugars, D- and L-cymaroses, from Cynanchum africanum R. Br.

Two glycosides named cynafoside-A (1) and -B (2) were isolated from Cynanchum africanum R. BR. (Asclepiadaceae) which is toxic to stock in South Africa. Their structures were determined on the basis of spectral and chemical evidence, and are unusual in that they include both D-and L-cymaroses in the sugar chain.

Perceptions of the magnitude and diversity of social support

Three studies were conducted to test the hypotheses that subjects would overestimate the proportion of their peers who shared their opinion on an issue and that they would perceive their own opinion group as consisting of people with a wider and more diverse range of values and outlooks than those holding different opinions. The first study was conducted following a period of intense debate about sixism on a college campus. Subjects estimated student opinion on issues related to sexism and indicated how diverse or similar they perceived supporters and nonsupporters of the women's movement to be. In a second study subjects estimated the proportion of students who evaluated President Carter's performance as good, fair, or poor and then indicated how diverse or similar the three groups of students were who held these various opinions. A third study closely replicated the second, using the issue of divestiture of college-owned stock in South Africa. In all three studies, subjects were divided into groups on the basis of their own attitudes. Results consistently supported the hypotheses.

Prehistoric Stock of South Africa

AT a meeting of the Royal Anthropological Institute (Section of Human Biology) on Jan. 8, Sir Arthur Keith exhibited a series of human skulls from the Matje River Rock Shelter, a newly discovered prehistoric site in the Zitzikamma District, on the coast of the Cape Province. The deposits in this rock-shelter, amounting to 21 feet in depth, were excavated by Prof. T. F. Dreyer, of Grey University College, Bloemfontein. The rock-shelter was first inhabited during the age of the ‘Mossel Bay’ culture, which is usually equated with one of the later palaœlithic cultures of Europe, and this culture was richly represented during the formation of the deeper strata, amounting in depth to 14 feet. All the remains from the Mossel Bay strata manifest racial traits, which were first revealed by the discovery of the large-brained Boskop skull in 1913. Three of the skulls from the deepest Mossel Bay strata have peculiar features of the forehead; the frontal bones appear compressed from side to side, with a high median keel. This malformation, known as trigonocephaly, occurs occasionally in modern races. A tendency to trigonism is not uncommon among Bushmen and Hottentots, who may be regarded as descendants of the prehistoric stock of South Africa. Sir Arthur Keith added that South Africa was the home of the most remarkable of all prehistoric peoples known to us, a people or stock tending to produce individuals with brains of remarkable dimensions and with a tendency for infantile and juvenile characters to persist into adult life, a tendency which Prof. M. R. Drennan has termed ‘pedomorphism’. Although remains of Bushmen have been found so far north as Lake Nyassa and Boskop remains in Northern Rho-desia, all the evidence at present points to South Africa as the evolutionary home of this prehistoric pedomorphic race.

On the Co-Relation of Various Diseases in Stock in South Africa

On the Co-Relation of Various Diseases in Stock in South Africa