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Existe poca información sobre los efectos de las fechas de siembra y los genotipos sobre la infestación de saltamontes (Zonocerus variegatus L.) y la acumulación de materia seca en el órgano radicular de la yuca. Se realizó un experimento en el sitio experimental de la Escuela de Agricultura y Ciencias de la Alimentación, de la Universidad de Njala durante las temporadas de cultivo 2007/2008 y 2015/2016. Este estudio evaluó los efectos de la fecha de siembra y los genotipos de yuca sobre la infestación de saltamontes y la acumulación de materia seca en la raíz de la yuca. El experimento utilizó cuatro genotipos de mandioca (Cacao, SLICASS 1, SLICASS 4 y SLICASS 6) y tres fechas de siembra (junio, septiembre y diciembre) dispuestos en un diseño de bloques completos aleatorizados (RCBD) con tres repeticiones. Los resultados mostraron que la incidencia y la gravedad de los ataques de saltamontes, así como el contenido de materia seca radicular, fueron significativamente diferentes (p

This study was conducted to evaluate the response of bush tea (Athrixia phylicoides DC.) to rainfall, relative humidity and temperature. Four sites, namely, Haenertsburg, Witvlag, and two sites at Khalavha in the Limpopo Province of South Africa were selected for investigation. Data on average rainfall, relative humidity and temperature were obtained 90 days prior to each field visit. During the five field visits over a 3-year period (2014–2016), bush tea plant height and stem diameter were measured and leaves were counted per plant. Correlation analyses suggested that bush tea height, stem diameter and number of leaves per plant significantly (p

This study evaluated the interaction of Bacillus subtilis (BD233) co-inoculation and mine water (75% MW) irrigation on the growth, nodulation, physiology and nutritional quality of cowpea. Three cowpea genotypes were exposed to four treatments namely i) Co-inoculation with B. subtilis (B+) and irrigation with 75% MW, ii) Co-inoculation with B. subtilis (B+) and tap water irrigation (0% MW), iii) No B. subtilis co-inoculation (B-) and irrigation with 75% MW and iv) No co-inoculation with B. subtilis (B-) and irrigation with tap water (0% MW) (control). A factorial experiment was repeated once in a glasshouse using a randomized complete block design with five replications. The results showed that at 125 DAP, Nyira and Asetanapa, not co-inoculated with B. subtilis (B-) and irrigated with 0% MW showed significantly higher number of branches per plant whilst Soronko irrigated with 0% MW but co-inoculated with B. subtilis (B+) had the tallest plants with a corresponding higher biomass compared to the other treatments. With 0% MW irrigation, Soronko and Nyira co-inoculated with B. subtilis (B+) had the highest nodule counts, plant pod counts, pod fresh weight, pod dry weight, number of seeds and seeds fresh weight per plant compared to Asetenapa and control. Co-inoculation with B. subtilis affected heavy metals (Ca, Fe, Zn, Mn & Al) accumulation in shoot and grain of the tested cowpea genotypes. These findings clearly suggest that B. subtilis has ability to sequester heavy metals in soils polluted with mine water and also enhance the growth, nodulation and yield of an important economic crop.

Nutrient-poor soils coupled with micronutrient deficiency among many rural resource-poor communities remain a challenge in sub-Saharan Africa. Nutrient-poor soils can be managed through various soil amendment or fertilisation strategies. Micronutrients can be supplied through plants. The study was aimed at determining the symbiotic nitrogen fixation of cowpea as well as the contribution of inter-cropping under varying levels of nitrogen, phosphorus, and potassium (NPK) fertilisation. In addition, the amount of micronutrients supplied by cowpea and amaranth were determined. The experiment was laid out in a 2 &times, 4 factorial treatment structure in a completely randomised design, with inter-cropping (cowpea and amaranth) and fertiliser (control, 25%, 50%, and 100% of the recommended NPK levels) as treatment factors with four replications. Symbiotic N2 fixation of cowpea decreased from 341&ndash, 448 kgN.ha&minus, 1 to 77&ndash, 91 kgN.ha&minus, 1 for the first year and 557&ndash, 227 kgN.ha&minus, 1 to 92&minus, 164 kgN.ha&minus, 1 for the second year with fertilisation. The iron and zinc nutritional yield increased (61&ndash, 210 g.ha&minus, 1 for first year and 304&ndash, 867 g.ha&minus, 1, for second year), proportional to fertiliser application to both crops. The research shows the benefits of leguminous crops in soil nutrient fertility and inorganic fertilisation with inter-cropping in managing micronutrient deficiency to meet the nutritional needs of rural communities.

Bacillus species are ubiquitous microorganisms that enhance growth in several crops as well as provide protection against pathogens. In this study, the effects of soil inoculation with B. subtilis BD233 on growth and development of sweet pepper (Capsicum annuum L.), Swiss chard (Beta vulgaris L.) and lettuce (Lactuca sativa L.), were investigated. Three treatments were employed: i) incubation with a lysogeny broth culture of B. subtilis BD233; ii) broth without B. subtilis BD233 (without BD233/control) and iii) tap water. Potting soil-grown seedlings of the three crops were assayed to measure growth parameters over a period of five weeks (35 days) after exposure to the treatments. Soil inoculation with B. subtilis BD233 significantly improved the growth and development of sweet pepper and lettuce seedlings relative to the other treatments but not for Swiss chard. Bacillus subtilis BD233 in lysogeny broth increased the plant height, stem elongation rate and stem diameter of sweet pepper and lettuce seedlings relative to those treated with water. Furthermore, the biomass of sweet pepper and lettuce seedlings exposed to B. subtilis BD233 was increased by 32.2 and 92.6%, relative to their respective controls. However, no statistical differences for height and biomass were found for Swiss chard in response to the treatments. The results of the study demonstrated the potential of B. subtilis BD233 to enhance the early growth of these non-indigenous vegetables in nutrient-poor African soils.

Lumichrome is a novel multitrophic signal molecule produced by rhizobia and plants that affects many physiological functions including seedling growth, root respiration, photosynthetic rates, leaf stomatal conductance and transpiration in several plant species. The effect of lumichrome on seed germination of four legumes (Rooibos, cowpea, Bambara groundnut and Kersting's bean), and three non-leguminous crops (traditional pumpkin, makataan and spinach), was investigated. All seeds were surface-sterilized and treated for 2 h with either of three levels of lumichrome (0, 5 or 50 nM). Seed germination (two replicates of ten seeds per crop) was done under sterile conditions using 9 cm-plastic petri dishes and Whatman No. 1 filter paper discs moistened with sterile distilled water. Treating legume seeds with nanomolar concentrations of lumichrome enhanced the seed germination percentage and rate of germination of Kersting's bean seeds, but not those of cowpea when compared to the control. Similarly, no significant differences in seed germination were recorded for Rooibos and Bambara groundnut, however, 9 days after treatment with lumichrome, slight stimulation of seed germination was observed for Rooibos and Bambara groundnut soaked in 5 nM lumichrome, compared to their respective controls. In response to nanomolar concentrations of lumichrome, non-leguminous crops also responded differently. A low nanomolar concentration of lumichrome (5 nM) significantly (p

Leading crops such as cotton, maize, rice and wheat were the first to be studied using omics technologies (genomics, transcriptomics, proteomics and metabolomics). Those crops that are considered l...

The classification of the legume family proposed here addresses the long-known non-monophyly of the traditionally recognised subfamily Caesalpinioideae, by recognising six robustly supported monophyletic subfamilies. This new classification uses as its framework the most comprehensive phylogenetic analyses of legumes to date, based on plastid matK gene sequences, and including near-complete sampling of genera (698 of the currently recognised 765 genera) and ca. 20% (3696) of known species. The matK gene region has been the most widely sequenced across the legumes, and in most legume lineages, this gene region is sufficiently variable to yield well-supported clades. This analysis resolves the same major clades as in other phylogenies of whole plastid and nuclear gene sets (with much sparser taxon sampling). Our analysis improves upon previous studies that have used large phylogenies of the Leguminosae for addressing evolutionary questions, because it maximises generic sampling and provides a phylogenetic tree that is based on a fully curated set of sequences that are vouchered and taxonomically validated. The phylogenetic trees obtained and the underlying data are available to browse and download, facilitating subsequent analyses that require evolutionary trees. Here we propose a new community-endorsed classification of the family that reflects the phylogenetic structure that is consistently resolved and recognises six subfamilies in Leguminosae: a recircumscribed Caesalpinioideae DC., Cercidoideae Legume Phylogeny Working Group (stat. nov.), Detarioideae Burmeist., Dialioideae Legume Phylogeny Working Group (stat. nov.), Duparquetioideae Legume Phylogeny Working Group (stat. nov.), and Papilionoideae DC. The traditionally recognised subfamily Mimosoideae is a distinct clade nested within the recircum-scribed Caesalpinioideae and is referred to informally as the mimosoid clade pending a forthcoming formal tribal and/or clade-based classification of the new Caesalpinioideae. We provide a key for subfamily identification, descriptions with diagnostic charactertistics for the subfamilies, figures illustrating their floral and fruit diversity, and lists of genera by subfamily. This new classification of Leguminosae represents a consensus view of the international legume systematics community; it invokes both compromise and practicality of use.

Bambara groundnut (Vigna subterranea (L.) Verdc.) [BGN] is an easy-to-cultivate vegetable crop neglected over the past years. It is a drought-tolerant crop with nutritional and medicinal values and as a result, the crop is referred to as nutraceuticals. Based on this, there exist a need to review the beneficial potential (nutraceutical value) of this neglected and underutilized crop to protect and promote its cultivation for food (source of nutrients) and medicines especially among rural poor communities in sub-Saharan Africa. This review systematically examines the background information and uses of BGN. The antimicrobial properties of BGN were also considered and examined to ascertain its nutraceutical importance. BGN has been reported as a crop possessing antioxidant and antimicrobial properties. Clinically, the extracts of BGN have been reported to exhibit antimicrobial activities against bacteria such as Klebsiella pneumoniae subsp. pneumoniae ATCC 700603, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus subsp. aureus ATCC 33591, Escherichia coli, Bacillus cereus, yeast (Candida albicans) and mold (Aspergillus niger). This review outlines the uses of BGN as a functional food crop as well as its nutraceutical and antimicrobial potentials. However, there exist paucity of knowledge and literature on the crop's antimicrobial activities especially against plant pathogens of economic importance. Hence, this review proposes that more research be geared towards assessing the nutraceutical value and antimicrobial potentials of this crop against plant pathogens of economic importance and the promotion of the crop's cultivation., Food Science; Nutrition; Agriculture; Nutraceuticals; Antimicrobial Potential; Bambara Groundnut; Antioxidants; Plant Pathogens; Phytochemicals.

Rooibos (Aspalathus linearis) plants are cultivated for the production of the Rooibos tea. In this work, biosorption process of Pb(II) from aqueous solution on Rooibos shoot powder (RSP) was studied in a batch process. The effect of experimental parameters such as solution pH (2–9), contact time (30–180 min) and initial Pb(II) concentration (25–400 mg L−1), adsorbent dosage (0.2–2.1 g), and temperature (25–80°C) on biosorption process was examined. In an attempt to determine the biosorption capacity and rate of Pb(II) removal, isotherm and kinetic data were modeled using different equations. To this end, the biosorption process by RSP followed the Langmuir model for Pb(II) ions (R2 = 0.9907), with maximum monolayer adsorption capacity of 18.90 mg g−1. Kinetic data were properly fitted with the pseudo-second order kinetic model, and it can be seen that the calculated qe (cal) value (11.31 mg g−1) agrees with the experimental value (12.80 mg g−1). Furthermore, the biosorbent showed good removal of P...

The use of Rooibos shoots, a natural adsorbent, for cadmium removal from wastewater is proposed. The effects of initial pH, adsorbent dosage, contact time, and initial concentration were investigated in the batch adsorption mode. The optimum pH was found to be 5.5. Isotherm and kinetic data were modeled; the data fitted best to the Freundlich model, and, kinetically, the adsorption was of pseudo-second order as shown by the high R2 value of 0.9928 along with close agreement between the experimental qe (13.9 mg g−1) and calculated qe (14.24 mg g−1) values. The studied biomass material was found to be effectively used for removal of cadmium from contaminated mine wastewater.

There is little information on in situ distribution of nutrient elements in N2-fixing nodules. The aim of this study was to quantify elemental distribution in tissue components of N2-fixing nodules harvested from Psoralea pinnata plants grown naturally in wetland and upland conditions in the Cape Fynbos. The data obtained from particle-induced X-ray emission revealed the occurrence of 20 elements (Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Sr, Y, Zr, Mo and Ba) in nodule components. Although, in upland plants, the concentrations of S, Fe, Si, Mn and Cu showed a steady increase from the middle cortex to the medulla region of P. pinnata nodules, in wetland plants, only S, Fe and Mn showed an increase in concentration from the middle cortex to the bacteria-infected medulla of P. pinnata nodules. By contrast, the concentrations of Cl, K, Ca, Zn and Sr decreased from middle cortex to nodule medulla. The alkaline earth, alkali and transition elements Rb, Sr, Y and Zr, never before reported in N2-fixing nodules, were found to occur in root nodules of P. pinnata plants grown in both wetland and upland conditions.

Aspalathus linearis (Burm. F.) R. Dahlg., commonly referred to as Rooibos tea, grows naturally in nutrient-poor, sandy, acidic soils (pH 3–5.3) with high aluminum concentration ranging from 110 to 275 μg Al g−1in the Cederberg’s mountainous areas in South Africa. Earlier studies found significant differences in Al concentration in organs of A. linearis, with roots having higher amounts (1262–4078 μg Al g−1), suggesting that the plant is capable of accumulating excess Al in acidic soils. Identification of the mineralogical constituents of organs of A. linearis using X-ray diffraction (XRD) analysis revealed the presence of an Al–Si complex (aluminosilicate or hydroxyaluminosilicate (HAS) species) in the shoot and root, possibly to internally ameliorate Al toxicity. In addition, A. linearis has specialized cluster roots that exude Al-chelating organic acid ligands such as citric, malic, and malonic acids. Organic acids can bind strongly to Al in the plant and rhizosphere to reverse its phytotoxic effects to the plants. Field and glasshouse studies revealed significant differences in pH between rhizosphere and nonrhizosphere soils of A. linearis and also showed that roots of the plant release OH−and HCO3−anions to raise rhizosphere pH possibly to immobilize Al through complexation. Furthermore, A. linearis is easily infected by arbuscular mycorrhizae (AM) fungi, but mycorrhizal associations are known to inhibit transport of metallic cations into plant roots. These features of A. linearis are perceived as good indicators for bioremediation; and the plant could, therefore, be a suitable candidate for phytoremediation technologies such as phytoaccumulation, phytostabilization, and phytodegradation. The environmental and economic implications of the potential of A. linearis to bioremediate Al-contaminated soils are briefly discussed. Furthermore, this review briefly highlights future studies investigating the utilization of the shoot of A. linearis as adsorbent for the removal of trace and (or) heavy metal from aqueous solutions.

The genus Psoralea (tribe Psoraleae, family Leguminosae) is indigenous to the Cape fynbos of South Africa and little is known about its symbiosis and/or adaptation. The aim of this study was to assess root nodulation and N2 fixation in eight of the 50 Psoralea species, as well as the biodiversity of their associated nodulating microsymbionts. The eight species studied (namely, Psoralea pinnata, Psoralea aphylla, Psoralea aculeata, Psoralea monophylla, Psoralea repens, Psoralea laxa, Psoralea asarina and Psoralea restioides) all had round-shaped, determinate type (desmodioid) nodules, and data from 15N natural abundance showed that they obtained 60–88% of their N nutrition from symbiotic fixation. These Psoralea species also transported their fixed-N as ureides (allantoin and allantoic acid) in the xylem stream, a symbiotic trait that links them very closely to the tribe Phaseoleae. Bacteria isolated from root nodules of the eight Psoralea species varied in phenotypic characteristics, nodulation promiscuity, and N2-fixing efficacy. Furthermore, 16S rDNA gene sequence data showed that Psoralea species can form root nodules with different soil bacteria, including Rhizobium, Mesorhizobium and Burkholderia strains. This is not only evidence of nodulation promiscuity, but also an indication of the species’ adaptation to the nutrient-poor, low-N, sandy acidic soils of the Cape fynbos.

Soils of the Cape Fynbos in South Africa are very low in nutrients, especially N and P, which affect bacterial growth and metabolism. In this study, the effect of supplying nitrate (14.8 and 59.3 mM NO 3 − ), ammonium (28.1 and 112.0 mM NH 4 + ) and phosphorus (1.4 and 5.7 mM P) to five N2-fixing and 11 non-nodulating bacterial strains isolated from root nodules of Psoralea species in the Cape Fynbos was assessed. The data revealed marked variation in the secretion of lumichrome, riboflavin and IAA into culture filtrate. There was generally greater production of lumichrome, riboflavin and IAA by the N2-fixing bacteria than those unable to nodulate P. pinnata and siratro, with much greater concentrations of lumichrome and riboflavin in culture filtrate at high P than low P. At low and high P, symbiotic strain TUT57pp produced 2.2-fold and 3.2-fold more IAA than TUT65prp and TUT33pap respectively, (two non-nodulating strains also with greater IAA production). Although ammonium nutrition has no effect on riboflavin production, it altered lumichrome concentrations in culture filtrate. While ammonium application had no effect, supplying bacterial cells with high nitrate concentration significantly decreased cellular production of lumichrome and riboflavin, two important symbiotic signal molecules. The observed nitrate inhibition of lumichrome and riboflavin biosynthesis and release is in addition to its depressive effect on nodulation and N2 fixation in symbiotic legumes.

Using thin-layer chromatography, 16 bacterial isolates from root nodules of 8 differentPsoralea species were quantitatively assessed for their exudation of the metabolites lumichrome, riboflavin and IAA in response to pH, salinity and temperature. Our data showed that the bacterial strains tested differed in their levels of secretion of the three metabolites. For example, strain AS2 produced significantly greater amounts of lumichrome at both pH 5.1 and 8.1, while strains RT1 and PI produced more lumichrome per cell at only pH 8.1. Strains API and RP2 also produced more riboflavin at pH 5.1 than at pH 8.1; conversely strain RTl secreted more riboflavin at pH 8.1 than at pH 5.1. TwoP. repens strains (RP1 and RP2) isolated from very saline environments close to the Indian Ocean produced significant levels of lumichrome and riboflavin at both low and high salinity treatments. However, strains ACI and LI (fromP. aculeata andP. laxa) even produced greater amounts of lumichrome and riboflavin at higher salinity (i.e. 34.2 mM NaCl) and probably originated from naturally saline soils. In this study, high acidity and high temperature induced the synthesis and release of high levels of IAA by bacterial cells. In contrast, there was greater strain secretion of lumichrome at lower temperature (10°C) than at high temperature (30°C). The variations in the secretion of lumichrome, riboflavin and IAA by bacterial strains exposed to different pH, salinity and temperature regimes suggest that genes encoding these metabolites are regulated differently by the imposed environmental factors. The data from this study also suggest that natural changes of pH, salinity and/or temperature in plant rhizospheres could potentially elevate the concentrations of lumichrome, riboflavin and IAA in soils. An accumulation of these molecules in the rhizosphere would have consequences for ecosystem functioning as both lumichrome and riboflavin have been reported to act as developmental signals that affect species in all three plant, animal, and microbial kingdoms.