The effect of desiccation on lipid content, fatty acid composition and the antioxidative enzymic capacity was investigated in seeds of Telfairia occidentalis, harvested at physiological and agronomic maturity. Seeds were dried at 5 and 28 o C, environments that induced different drying and metabolic rates. Desiccation of seeds was associated with decreased antioxidative enzymic capacity (of peroxidase and polyphenoloxidase), and thus increased likelihood of free radical attack and decreased viability (germinability). Agronomically mature seeds contained predominantly saturated fatty acids (tridecanoic), with very low levels of the major fatty acids of edible oilseeds (palmitic, stearic or the unsaturated C18 fatty acids). There was increased accumulation of the mono-unsaturated (oleic) and polyunsaturated (linoleic) fatty acids when seeds were dried at 28 o C and moisture contents have reduced to about 42 % or lower. In contrast, seeds dried at 5 o C maintained high levels of saturated fatty acids and lower levels of monounsaturated or polyunsaturated fatty acids. Results suggest the need to develop different post-harvest protocols for seed storage, and for processing T. occidentalis to 'improve' the seed fatty acid profile as an oilseed for human and animal food.

No abstract

No abstract

Yams are Dioscoreaceae grown in the tropics and sub-tropics and used as food and for related pharmaceutical properties. The South Western Region of Cameroon is a major yam producing zone. This study which evaluates morphological variability between ten linguistically different yam types grown in South Western Cameroon will serve as a necessary step for subsequent genetic study of the species. The yams, collected from nine sites, were planted in a completely randomized design in four locations. Analysis of data on nine morphological vines traits reveals that, the yam types constituted five main clusters. Cluster 1 with 61.3% similarity consists of five accessions of D. rotundata-Ikom, Calabar, White, Agar and Igbo yams. This cluster has three subgroups with 84.9% similarity. Cluster 2 consists of Yellow yam (D. cayenensis) with 48.5% similarity to members of Cluster 1. Ghana Water yam and Swệt yam constitute Cluster 3 with 83.4% similarity while Sugar yam and Water yam constitute the 4th and 5th clusters respectively. The ten yam types are actually five cultigens-rotundata, rotundatacayenensis complex, cayenensis, dumetorum and alata; and the significant variability (P<0.05) observed with respect to the morphological characters evaluated may be the basis for the linguistic polymorphism noticed in the naming of the different yam types. Although genetic analysis is recommended to determine firm similarities, the establishment of clear links remains problematic because of the high hybridisation noticed among members of the Dioscoreaceae; and considering that yams types were introduced in the zone from different lands over many centuries.

Objective: Changing forest composition and structure caused by selective logging may affect forest phenology either alone or in combination with other environmental factors. The present study aims to analyze the phenological pattern of some exploitable timber tree species in two forest types. Methodology and Results: Eleven economically important tree species were selected for monitoring at three DBH size classes using the crown density method originally devised by Koelmeyer (1959). Quantitative monthly data were collected from September 2011 to December 2014 for the timing, duration and frequency of flowering, and fruiting. A total of 58 individuals were observed in both forest types. There was a significant difference between forest types and species for flowering (p≤0.001) and fruiting (p≤0.001). However, there was no significant difference in flowering and fruiting between individuals of the same species in both forest types. Flowering occurred during the light wet season and fruiting during the heavy wet season to ensure the availability of seeds to germinate into seedlings. Conclusions and application of findings: Phenology was mainly constrained by the biotic determinants of phenology. However while the determinants of phenology are intact in the unlogged forest types, they are destabilized by selective logging causing an alteration in plant species. Thus, activities that are specifically designed to enrich selectively logged sites are necessary in order to promote the natural regeneration of timber species after selective logging.