A checklist of rheophytes of Cameroon

Rivers in Cameroon were surveyed to collect and document rheophytic plants. Rheophytes are the dominant aquatic macrophytes in tropical river systems, where they are adapted to extreme environments of rushing water (e.g., river rapids, waterfalls and flash floods). Rheophytic plants are useful indicators of river health. However, their habitats are threatened by human activities such as agriculture, plantation development, alluvial mining and dam construction, particularly in tropical countries. In this survey we documented 66 rheophytic species in 29 genera and 16 families. Two ferns, 8 monocotyledons and 56 dicotyledons were listed. Apart from the Podostemaceae family in which all species are rheophytic, the other 15 families have few species which are rheophytic. Five of these families have up to four species and the remaining 10 have only one member as a rheophytic species. The conservation status of each species is assessed and discussed. This work urges botanists, conservationists, and policy makers to do more to protect the habitats of rheophytes and put in place strategies and action plans for the conservation of this important biological group

The distribution of Podostermaceae in Ghana

The distribution of five species of Podostemaceae, namely, Ledermanniella bowlingii, Polypleurum submersum, Saxicolella agumatsa, Saxicolella amicorum and Tristicha trifaria occurring in Ghana has been described. T. trifaria is widespread in the country. The other Podostemaceae species are at present known from one, two or three rivers. S. agumatsa was found on the cliff surface of the Wli falls on the Agumatsa river. L. bowlingii and P. submersum were found in two rivers, namely, Asuboni river, near Kwahu Nteso and Akrum river, near Begoro. S. amicorum occurred in three rivers in different geographical areas: in Ankasa river in the Ankasa Resource Reserve, in the Kakum river near Asuansi and in Nwhini river, near Aduabrim. All the five species occurred in the wet semi-equatorial climate type. T. trifaria is known from the dry equatorial and tropical continental climate types. S. amicorum and T. trifaria were found in the semi-equatorial climate type. T. trifaria occurs in both low and high rainfall areas, from areas with less than 1000 mm to areas above 1900 mm of rainfall y-1. The other species are confined to higher annual rainfall areas of 1250 to above 1900 mm. In Ghana Podostemaceae were found to occur on older rocks of the Precambrian and Palaeozoic eras, and not on rocks of recent origin. They occur between 75–900 m above sea level. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 2 No. 1 (2000) pp. 31-3

Nutrient and Anti-Nutrient Composition of Four Rice Varieties in Port Harcourt Metropolis

This study evaluated the nutrient and anti-nutrient content of four rice varieties in Port Harcourt metropolis. Four rice varieties (Tomato gold TG, Mama’s pride MP, Ultimate gold UG and daily choice DC) were used in this study. The rice varieties were purchased, milled into fine flour and evaluated for proximate, mineral and anti-nutrient analysis using standard methods. Proximate composition of the rice varieties revealed that moisture content ranged from 11.51-12.80%, ash (0.45-0.60%), fat (0.39-1.39%), crude protein (5.73-6.07%), crude fibre (0.90-6.85%) and carbohydrate (73.67-80.09%). Mama’s pride rice variety contained higher ash and fat contents while Tomatoes gold had significantly higher crude fibre. On the other hand, ultimate gold rice variety contained higher protein and carbohydrate; however, ash, protein and moisture contents did not vary significantly (p>0.05) between the rice varieties. Mineral composition of the rice varieties also showed that magnesium content ranged from 6.28-9.63 mg/100 g, calcium (3.74-8.23mg/100g) and iron (1.50-5.48mg/100g). The concentration of these mineral elements was found to be superior in ultimate gold rice variety. Phenol content of the rice varieties ranged from 9.92-14.58mg/100g, phytate (1.22-1.53g/kg), saponin (5.86-6.37%), tannin (47.03-66.89 mg/100 g) and flavonoid (2.29-2.80%). Ultimate gold rice variety also contained higher concentrations of phenol and tannins while saponin content was higher in daily choice rice variety. Phytate content on the other hand did not vary significantly (p>0.05) between the rice varieties. The result therefore revealed that ultimate gold rice variety contained a considerable amount of nutrients and should be highly recommended to consumers for derivation of the above-mentioned nutrients

Industrial Applications of Cyanobacteria

Cyanobacteria also known as blue-green algae are oxygenic photoautotrophs, which evolved ca. 3.5 billion years ago. Because cyanobacteria are rich sources of bioactive compounds, they have diverse industrial applications such as algaecides, antibacterial, antiviral and antifungal agents, hence, their wide use in the agricultural and health sectors. Cyanobacterial secondary metabolites are also important sources of enzymes, toxins, vitamins, and other pharmaceuticals. Polyhydroxy- alkanoates (PHA) which accumulate intracellularly in some cyanobacteria species can be used in the production of bioplastics that have properties comparable to polypropylene and polyethylene. Some cyanobacteria are also employed in bioremediation as they are capable of oxidizing oil components and other complex organic compounds. There are many more possible industrial applications of cyanobacteria such as biofuel, biofertilizer, food, nutraceuticals, and pharmaceuticals. Additionally, the metabolic pathways that lead to the production of important cyanobacterial bioactive compounds are outlined in the chapter along with commercial products currently available on the market

Phylogenomics and the rise of the angiosperms

International audienceAngiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods 1,2 . A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome 3,4 . Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins 5–7 . However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes 8 . This 15-fold increase in genus-level sampling relative to comparable nuclear studies 9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade

Phylogenomics and the rise of the angiosperms.

Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins5-7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade