Hannington Oryem-Origa

Effects of heat and fire on the germination of Acacia sieberiana D.C. and Acacia gerrardii Benth. in Uganda

The effects of heat treatment and fire on seed germination of Acacia sieberiana D.C. and Acacia gerrardii Benth. were studied. Dry heat and fire were studied separately. Seeds treated with dry heat were set to germinate in petri-dishes under laboratory conditions. Other seeds were planted in plots at the Uganda Institute of Ecology, Mweya, which were then burnt, and subsequent seedling emergence was monitored. The effect of heat treatment on seed germination depended on heat intensity and duration of exposure. Higher intensities reduced the germination capacity of Acacia seeds. Short exposure of seeds stimulated germination but prolonged exposure rapidly reduced seed viability. A. sieberiana had a higher heat resistance than A. gerrardii . The survival and germination of seeds after fire increased with depth of burial and A. sieberiana survived better than A. gerrardii . The germinability of seeds of A. gerrardii was not significantly increased by fire.

Medicinal plants of Otwal and Ngai Sub Counties in Oyam District, Northern Uganda

BackgroundAn ethnobotanical study was carried out in four parishes in the Ngai and Otwal Sub Counties in Oyam district, Northern Uganda, where insurgency has been prevalent for the past 20 years. Documenting medicinal plant species used in treating various health conditions among the local people.MethodsInformation was obtained from mainly the local population, the traditional healers and other experienced persons through interviews, formal and informal discussions and field excursions.ResultsSeventy one plant species were reported for use in the treatment of various diseases in the study area. These plant species belongs to 41 families, with Asteraceae being the most represented. Roots were ranked the commonest plant part used. Oral administration was the most frequently used route of administration. A total of 41 different health conditions were reported to be treated by use of medicinal plant species. Thirty nine percent of the recorded plant species were reported for treating stomach related ailments.ConclusionThe use of medicinal plants in primary healthcare is still a common practice in Ngai and Otwal Sub Counties. The trust they have is built on the curative outcome properties claimed, poverty and armed conflict that lead to inadequate healthcare facilities. The generation gap caused by the over 20 years of insurgency in the area has brought about knowledge gap on the usage of medicinal plant species between the young and the older generation.

Dynamics of plant species during phytostabilisation of copper mine tailings and pyrite soils, Western Uganda

Introduction: Destruction of vegetation resources emanating from deposition of mine wastes is a serious environmental problem. Conventional plant species restoration methodologies are costly and fe ...

Antibacterial and Antifungal Properties of Some Wild Nutraceutical Plant Species from Nebbi District, Uganda

Aims: The purpose of this study was to investigate the antibacterial and antifungal properties of selected wild nutraceutical plants from Nebbi district in Uganda. Study Design: Experimental study.

Phytoremediation potential of Leucaena leucocephala (Lam.) de Wit. for heavy metal-polluted and heavy metal-degraded environments.

Regeneration of heavy metal-polluted and heavy metal-degraded sites has remained a global challenge despite the existence of numerous conventional physico-chemical techniques that can be applied. In view of the large size of the degraded areas and the cost implications, the application of the inexpensive “green” and sustainable technique of phytoremediation is unrivalled by any other possible alternative techniques. However, its effectiveness is largely dependent on judicious selection of the plant to be used. We thus assessed the suitability of Leucaena leucocephala for phytoremediation of heavy metal-polluted and heavy metal-degraded sites. L. leucocephala has numerous inherent characteristics that can be exploited to augment phytoremediation and lower the cost of regeneration. The species can survive in harsh environmental conditions with the exception of heavily frosted conditions and occurs in a wide range of ecological settings. The species is fast growing, capable of reaching maturity in 6 to 7 months to produce a vast amount of seeds that can germinate into numerous seedlings to carry on further remediation of the polluted site. It can produce large quantities of phytomass that can accumulate heavy metals and can repeatedly be harvested to regenerate a polluted area through phytoextraction. Heavy metal-laden phytomass of L. leucocephala moulds into furniture and is used for construction to preclude contamination at the site of use. It is excellent on coppicing, thus eliminating the costs of replanting during the phytoremediation programme. The species is endowed with high proficiency for nitrogen fixation through nodule formation and can substantially revitalize microbial mass and micro-bioactivities to pave way for re-establishment of self-sustaining plant communities over the polluted sites. Its flexibility to nodulate with rhizobia of other legumes and its rhizobia to nodulate with other legumes could optimize nitrogen content revitalization of the polluted soils. However, the species is invasive and could be adopted under stringent measures to avoid its spread. It is also very palatable to animals and may thus be of limited application in the phytoremediation of areas accessible to animals. Suitability of the species in heavily polluted areas is minimal as many of the inherent characteristics may not fully be expressed.

Regeneration of an afromontane forest following agricultural encroachment in southwestern Uganda.

A study of the regeneration of an Afromontane forest was carried out in Mgahinga Gorilla National Park (MGNP), southwestern Uganda, following agricultural encroachment in the last 50 years. The landscape was changed by terracing and removing the indigenous vegetation and replacing it with exotic tree species. This study also examined the soil nutrient status of the formerly encroached area in the park. Species richness of indigenous trees was high in the formerly cultivated area. Twenty-six indigenous species were found in the formerly cultivated area, compare dwith 20 species in the natural forest and 12 species of indigenous trees found under exotic woodlots. There was a significant difference in species richness and density in the three habitat types. The natural forest supported the highest stem density (75%),and the lowest stem density (4%) was recorded under exotic woodlots. Seedlings(<2 cm diameter at breast height) accounted for the majority of juveniles in the three habitats. The natural forest h...

WILD ROBUSTA COFFEE (COFFEA CANEPHORA FROEHNER) SEEDLING RECRUITMENT AND SURVIVAL IN KIBALE NATIONAL PARK, UGANDA

ABSTRACT Survival of wild robusta coffee (Coffea canephora) seedlings on the forest understorey in Kibale National Park was monitored and analyzed in response to a number of mortality factors, such as fungal diseases, herbivory, desiccation, trampling, and litter of other plant species. A comparison was made with wild coffee seedlings germinated in the laboratory and transplanted in the Botanic Garden under two light conditions. There was a general decrease in the number of coffee seedlings with time under all treatments and in all sites. Seedling mortality rate was initially rapid but later slowed down to a steady rate. Seedling mortality was highest on plots with intact ground vegetation cover and lowest on plots without ground vegetation and leaf litter. In the Botanic Garden, seedlings grown on plots partially illuminated had a much lower mortality rate and longer half-life than those grown on fully illuminated plots. Fungal infection affected the largest percentage of coffee seedlings, followed by he...