Search

Tropical East Africa (TEA) is one of the most important biodiversity hotspots on the planet. Its rich flora diversity and inventory have been clearly recognized after the publication of the last volume of the Flora of Tropical East Africa (FTEA) in 2012. However, many new and newly recorded taxa have been named and documented since the publication of the first volume of FTEA in 1952. In this study, we comprehensively compiled new taxa and new records by reviewing the literature on the taxonomic contributions of vascular plants in TEA from 1952 to 2022. Our list includes 444 new and newly recorded species belonging to 81 families and 218 genera. Among these taxa, 94.59% of the plants are endemic to TEA and 48.42% are herbs. Additionally, members of Rubiaceae and Aloe are the most numerous family and genus respectively. These new taxa are unevenly distributed in TEA, but are found mainly in areas of high species richness, such as coastal, central and western areas of Kenya, central and southeastern Tanzania. This study offers summative assessment of the newly recorded flora inventory in TEA and provides recommendations for future research on plant diversity survey and conservation. [ABSTRACT FROM AUTHOR]

Nairobi River tributaries are the main source of the Athi River. The Athi River basin is the fourth largest and important drainage system in Kenya covering 650 km and with a drainage area of 70,000 km. Its water is used downstream by about four million people not only for irrigation but also for domestic purposes. However, its industrial, raw sewer, and agricultural pollution is alarming. In order to understand distribution and concentration of heavy metals and nutrients in the water of Nairobi River, 28 water samples were collected in the rainy season (October) of 2015 and dry season (June) of 2016. Cd, Cu, Cr, Zn, As, Pb, Fe, Ni, Mn, NO , and TP were analyzed. Only Cr, Pb, Fe, and Mn had concentrations exceeding the WHO permissible limit for drinking water. Out of the 28 sites examined in the study, one site had Pb exceeding the WHO recommended level. Similarly, three sites exceeded the same level for Cr. Only three sites were within the WHO permissible limits for drinking water for Mn while just four sites were within USEPA limit for Fe. Industrial effluent, domestic sewerage, agricultural activities, and solid waste were the main sources of pollution. Significant spatial variation of both heavy metals and nutrients concentration was observed and emanated from point source pollution. Eleven out of 31 macrophytes species that were identified along the river and its tributaries are effective heavy metal and nutrient bioaccumulators and may be used in phytoremediation. [ABSTRACT FROM AUTHOR]

Medicinal plants are vital sources of easily accessible remedy used in the countryside healthcare system. This study aimed to find and make record of plants that are used for medicinal therapy by three communities living in Cherangani Hills. So far no single study has documented medicinal plants as a whole in the area. Ethnobotanical data were obtained through interviewing informants using semi-structured questionnaires and extracting information from journals and books. Descriptive statistical analysis was applied to describe the data. Overall 296 plant species from 80 families and 191 genera were identified. Asteraceae family was the most dominant, representing 10.7% of the total plant species recorded. Roots (35.9%) represented the most commonly used parts of the plant. The commonly used method of preparation was decoction (54.9%). The reported diseases were classified into 14 diverse ailment groups out of the 81 health conditions on their underlying user reports. Rural communities in Cherangani Hills are rich sources of plants with medicinal properties. Therapeutic uses of the compiled plants provide basic information that can aid scientists to conduct additional research dedicated to conservation of species and pharmacological studies of species with the greatest significance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reconstruction of relationships of Dendrosenecio based on plastid phylogenomics. • A strong distinction between the Tanzanian and Kenya-Uganda clades. • Origin of Dendrosenecio was instigated by the Plio-Pleistocene. • Main diversification was recent and rapid possibly due to climatic factors. Giant senecios (Dendrosenecio , Asteraceae), endemic to the tropical mountains of Eastern Africa, are one of the most conspicuous alpine plant groups in the world. Although the group has received substantial attention from researchers, its infrageneric relationships are contentious, and the speciation history remains poorly understood. In this study, whole chloroplast genome sequences of 46 individuals were used to reconstruct the phylogeny of giant senecios using Maximum Likelihood and Bayesian Inference methods. The divergence times of this emblematic group were estimated using fossil-based calibrations. Additionally, the ancestral areas were inferred, and ecological niche modeling was used to predict their suitable habitats. Phylogenetic analyses yielded two robustly supported clades. One clade included taxa sampled from Tanzania, while the other clade included species from other regions. Giant senecios likely originated from the North of Tanzania approximately 2.3 million years ago (highest posterior density 95%; 0.77–4.40), then rapidly radiated into the Kenyan and Ugandan mountains within the last one million years. The potential routes of dispersal have been proposed based on the inferred ancestral areas, estimated time, and predicted past suitable niches. Plio-Pleistocene climate oscillations and orogeny instigated early divergence of the genus. Whereas in situ radiation of giant senecios was chiefly driven by multiple long-distance dispersal events followed by episodes of vicariance, and allopatric speciation (geographic and/or altitudinal). [ABSTRACT FROM AUTHOR]

Background: Polystachya Hook. is a large pantropical orchid genus (c. 240 species) distributed in Africa, southern Asia and the Americas, with the center of diversity in Africa. Previous studies on species of this genus have not obtained the complete chloroplast genomes, structures and variations. Additionally, the phylogenetic position of the genus in the Orchidaceae is still controversial and uncertain. Therefore, in this study, we sequenced the complete plastomes of six Kenya Polystachya species based on genome skimming, subjected them to comparative genomic analysis, and reconstructed the phylogenetic relationships with other Orchidaceae species., Results: The results exhibited that the chloroplast genomes had a typical quadripartite structure with conserved genome arrangement and moderate divergence. The plastomes of the six Polystachya species ranged from 145,484 bp to 149,274 bp in length and had an almost similar GC content of 36.9-37.0%. Gene annotation revealed 106-109 single-copy genes. In addition, 19 genes are duplicated in the inverted regions, and 16 genes each possessd one or more introns. Although no large structural variations were observed among the Polystachya plastomes, about 1 kb inversion was found in Polystachya modesta and all 11 ndh genes in the Polystachya plastomes were lost or pseudogenized. Comparative analysis of the overall sequence identity among six complete chloroplast genomes confirmed that for both coding and non-coding regions in Polystachya, SC regions exhibit higher sequence variation than IRs. Furthermore, there were various amplifications in the IR regions among the six Polystachya species. Most of the protein-coding genes of these species had a high degree of codon preference. We screened out SSRs and found seven relatively highly variable loci. Moreover, 13 genes were discovered with significant positive selection. Phylogenetic analysis showed that the six Polystachya species formed a monophyletic clade and were more closely related to the tribe Vandeae. Phylogenetic relationships of the family Orchidaceae inferred from the 85 chloroplast genome sequences were generally consistent with previous studies and robust., Conclusions: Our study is the initial report of the complete chloroplast genomes of the six Polystachya species, elucidates the structural characteristics of the chloroplast genome of Polystachya, and filters out highly variable sequences that can contribute to the development of DNA markers for use in the study of genetic variability and evolutionary studies in Polystachya. In addition, the phylogenetic results strongly support that the genus of Polystachya is a part of the tribe Vandeae., (© 2022. The Author(s).)

Current study was conducted to assess remediation efficiency of heavy metals in Thika waste water treatment plant, human health risk posed by consumption of vegetables irrigated with its reclaimed waste water, and vegetables supplied at Makongeni market. Concentration of Cu, Zn, Cr, Ni and Pb was investigated in the sludge, waste water and vegetables, spinach (Spinacea oleracea), kales (Brassica oleracea var. acephala) and coriander (Coriandrum sativum). Thika waste water treatment plant was efficient in heavy metal remediation. Effluent heavy metal concentration was within recommended concentration for irrigation. Dietary intake of heavy metals and target hazard quotient were used to evaluate health risk posed to consumers. Heavy metals concentrations of vegetables sampled and analyzed were within world health organization permissible limit. Thika waste water treatment plant was found to be efficient; however, regular dredging is essential to reduce accumulated heavy metals in the sludge. Moreover, the study outcome revealed that besides reclaimed waste water that may be perceived to pose great health risk to consumers, the whole food production and distribution chain should be monitored to guarantee food safety., (Copyright © 2018 Elsevier Ltd. All rights reserved.)