Musa Spp Research Articles

Bactericidal Effect of the Leaf Extract from Musa spp. (AAB Group, Silk Subgroup), cv. "Manzano" Against Multidrug-Resistant Mycobacterium tuberculosis.

Air-dried leaves of a Musa spp. AAB, cv. “Manzano” plant, known as Ja'as in the Maya culture, were sequentially extracted with hexane, ethyl acetate, and methanol; the resulting extracts were investigated for their antimycobacterial activity against susceptible and drug-resistant strains of Mycobacterium tuberculosis (MTB) using the Microplate Alamar Blue Assay. Both the n-hexane extract (HE) and ethyl acetate extract (EE) showed potent activity against both strains of MTB, with the EE exhibiting the strongest activity and a Minimum Inhibitory Concentration of 12.5 and 6.25 μg/mL against susceptible and drug-resistant strains, respectively. Both extracts also demonstrated a mycobactericidal effect and a very good selectivity index when tested for cytotoxic activity on Vero monkey kidney cells, using the Sulforhodamine B assay. Our results demonstrate the efficiency and selectivity of Musa spp. AAB, cv. “Manzano” against MTB strains and support its traditional use as remedy against tuberculosis in Maya traditional medicine.

Meta-analysis of the strategies for management of Cosmopolitis sordidus Guermar in Musa spp.

Meta-analysis of the strategies for management of Cosmopolitis sordidus Guermar in Musa spp.

Molecular Markers and Their Application in Fusarium Wilt Studies in Musa spp

Bananas and plantains (Musa spp.) are an important socio-economic fruit crop grown worldwide. Their production across the regions where they are grown is largely hampered by pests and diseases. Fusarium wilt is a disastrous diseases of bananas caused by the fungal pathogen Fusarium oxysporum f.sp. cubense (Foc). Managing it with chemicals, biological control agents and cultural methods is ineffective. Host plant resistance is the most effective and durable approach of managing most pest and disease epidemics in most plant species and could equally be effective in managing Fusarium wilt in bananas. Crossbreeding as one of the ways to introgress disease resistance genes and phenotyping for biotic and abiotic stresses currently used in banana breeding is apparently difficult to apply because of banana’s low fertility, gigantic size, and long-life cycle which prolongs its breeding cycle. There is, therefore, a need to apply molecular markers in banana genetic improvement for Fusarium wilt resistance because of their accuracy, speed, robustness and effectiveness of operation. The objective of this article was to review and discuss molecular markers that have been successfully used in studying Fusarium wilt in bananas and some other important crops. Molecular markers discussed in this article include Random Amplified Polymorphic DNA, Sequence Characterized Amplified Region, Simple Sequence Repeat, Inter-Simple Sequence Repeat, and Single Nucleotide Polymorphism. The information discussed in this article informs future decisions to identify suitable marker systems for fine mapping of target regions and accelerated identification of quantitative trait loci for Foc resistance in bananas.

Evaluation of banana germplasm and genetic analysis of an F1 population for resistance to Fusarium oxysporum f. sp. cubense race 1

Fusarium wilt of bananas (Musa spp.), caused by Fusarium oxysporum f. sp. cubense (Foc) causes up to 100% yield loss in bananas. Foc race 1 in particular is very devastating to dessert bananas in Uganda. One of the effective control strategies for the disease is the development of resistant cultivars through breeding. The objectives of this study were to identify suitable banana germplasm for generating a segregating population for resistance to Foc race 1 and understand the mode of inheritance of resistance to Foc race 1. Twenty-two banana accessions sourced from the National Agricultural Research Organisation in Uganda were challenged with Foc race 1 in a screen house experiment. Monyet, resistant to Foc race 1 and Kokopo, susceptible, were selected and crossed to generate 142 F1 genotypes. These F1 genotypes were also challenged with Foc race 1 in a screen house experiment. Data were collected on rhizome discoloration index (RDI), leaf symptom index (LSI) and pseudo-stem splitting (PSS), and analysed for variability. The banana accessions evaluated showed varying degrees of resistance to Foc race 1. Segregation ratios for resistant versus susceptible progenies fitted 13:3 (χ2 = 0.12, P = 0.73) for RDI and 11:5 (χ2 = 3.04, P = 0.08) for PSS. Estimated broad sense heritability was 27.8% for RDI, 13.9% for LSI and 14.7% for PSS. The results suggest that resistance to Foc race 1 in banana is controlled by at least two dominant genes with epistatic interaction and that heritability of resistance to Foc race 1 is low in Musa spp.

Association genetics of bunch weight and its component traits in East African highland banana (Musa spp. AAA group)

Key messageThe major quantitative trait loci associated with bunch weight and its component traits in the East African highland banana-breeding population are located on chromosome 3.Bunch weight increase is one of the major objectives of banana improvement programs, but little is known about the loci controlling bunch weight and its component traits. Here we report for the first time some genomic loci associated with bunch weight and its component traits in banana as revealed through a genome-wide association study. A banana-breeding population of 307 genotypes varying in ploidy was phenotyped in three locations under different environmental conditions, and data were collected on bunch weight, number of hands and fruits; fruit length and circumference; and diameter of both fruit and pulp for three crop cycles. The population was genotyped with genotyping by sequencing and 27,178 single nucleotide polymorphisms (SNPs) were generated. The association between SNPs and the best linear unbiased predictors of traits was performed with TASSEL v5 using a mixed linear model accounting for population structure and kinship. Using Bonferroni correction, false discovery rate, and long-range linkage disequilibrium (LD), 25 genomic loci were identified with significant SNPs and most were localized on chromosome 3. Most SNPs were located in genes encoding uncharacterized and hypothetical proteins, but some mapped to transcription factors and genes involved in cell cycle regulation. Inter-chromosomal LD of SNPs was present in the population, but none of the SNPs were significantly associated with the traits. The clustering of significant SNPs on chromosome 3 supported our hypothesis that fruit filling in this population was under control of a few quantitative trait loci with major effects.

Ploidy level and nucleotide variations in inflorescence dichotomous cultivars of plantain (Musa spp. AAB genome)

BackgroundInflorescence dichotomy in Musa species is a rare developmental event which leads to the production of multiple bunches on a single pseudostem at fruiting. In spite of its fascinating attraction and seductive appeal, little is known about the cytogenetic basis and molecular mechanisms that could be ascribed to this phenomenon. To bridge this gap in information, an integrative approach using cytological fingerprinting and DNA ploidy level profiling (based on chromosome counting and flow cytometry) were assayed on five inflorescence dichotomous plantain varieties and a single-bunching cultivar that served as control. This was done to assess the number and behaviour of chromosomes on the one hand and single nucleotide polymorphisms identified during analysis of nucleotide variations on the other.ResultsChromosomes stained with aceto-orcein were very tiny, compact, metacentric and acrocentric, and differed both in number and ploidy level between the inflorescence dichotomous and single-bunching cultivars. The dichotomous plantains were mainly diploid (2n = 2x = 22) while the single-bunching ‘Agbagba’ cultivar was consistently a triploid (2n = 3x = 33), as revealed by histological chromosome counting and flow cytometry, implying that there was a high incidence of genomic divergence on account of ploidy variations among the different Musa cultivars. Molecular genotyping using single nucleotide polymorphisms detected on the GTPase-protein binding gene of the leaf tissue gene complex provided further evidence indicating that differences in the number of bunches among the inflorescence dichotomous cultivars could be ascribed to nucleotide diversity that was elicited by changes in amino acid sequences in the genome of the crops. Non-synonymous nucleotide substitutions resulted mainly from transversion (from purine to pyramidine and vice versa), tacitly implying that these changes were crucial and promoted a cascade of reactions in the genome that were, probably, responsible for the non-persistence of the dichotomization event(s) or the reversals in the bunch phenotype detected among the inflorescence dichotomous cultivars.ConclusionsThis is the first report of cytogenetic fingerprints and nucleotide diversity detection among single- and multiple-bunching Musa cultivars. A clear distinction between the two groups was found that is indicative of variations both in ploidy level and nucleotide sequences. The pattern of single nucleotide polymorphisms provided profound clues suggesting that there was a high incidence of genomic divergence, due to random and unstable genetic events that were triggered by frequent spontaneous somatic mutations.

The Efficiency of Hybridization and Seed Production in Musa spp

The Efficiency of Hybridization and Seed Production in Musa spp

Banana peduncle – A green and renewable heterogeneous base catalyst for biodiesel production from Ceiba pentandra oil

In the present study, the feasibility of utilizing Musa spp “Pisang Awak” peduncle derived ash as a highly effective renewable heterogeneous basic catalyst for transesterification of underutilized non-edible Ceiba pentandra oil (CPO) was investigated. The physiochemical characteristics of the calcined banana peduncle (CBP) were studied by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy and Energy Dispersive Atomic X-ray spectroscopy (SEM-EDAX). Biodiesel was produced by a two-step esterification-transesterification process. In the first step, FFA content of the oil was reduced from 7% to 1.6% using reaction conditions of 1.0 vol% H2SO4 concentration, 1h reaction time, 1:4 v/v methanol to oil volumetric ratio with constant reaction temperature of 60 °C. In the second step, response surface methodology (RSM) using central composite design (CCD) was employed to determine the optimal process conditions of transesterification process variables. Based on the RSM results, the optimum process conditions for transesterification of CPO into fatty acid methyl ester (FAME) was found to be 1.978 wt% catalyst concentration, 60 min reaction time, 9.20:1 methanol to oil molar ratio with a maximum predicted FAME yield of 99.36% which was evaluated experimentally as 98.69 ± 0.18%.

Toxicity of the hydroalcoholic extracts of fruit leaves from the Peruvian Amazon in Artemia salina

Background: Medicinal plants have been used since ancient times, receiving interest in their healing potential because of their active components. The Amazon rainforest in the east of Peru has great diversity of flora, especially monocotyledons (Cocos nucifera, Mauritia flexuosa and Coffea spp.) and dicotyledons (Theobroma cacao L. and Musa spp. The toxicity of the hydroalcoholic extract of plant leaves from the Peruvian Amazon in Artemia salina was evaluated in this study. Methods: The leaves of the plants Cocos nucifera, Mauritia flexuosa, Theobroma cacao L., Coffea sp, and Musa sp were collected in the district of Cacatachi, San Martín. Phytochemical analysis of the leaves was carried out to identify their active components. The eggs of Artemia salina were provided by the Department of Animal Physiology of Universidad Nacional de Trujillo. The hydro-alcoholic extraction was carried out via the maceration method using 300 g of leaves and 500 mL of 96% ethanol for 15 days in agitation. The solutions were taken to a vertical rotavapor to obtain dry extracts and concentrations of 10, 100 and 1000 μL/ml were prepared. To test toxicity, 10 larvae were given the extract for each plant species and concentration in triplicate. The CL50 toxicity of Artemia salina samples was classified as: ˃ 1000 μL/ml (non-toxic), 500˂CL50 ≤ 1000 (low toxicity), 100˂CL50 ≤ 500 (moderate toxicity), CL50˂100 (high toxicity). Results: It was observed that Mauritia flexuosa and Musa sp. at concentrations of 10, 100 and 1000 μL/ml have high, medium and low toxicity, respectively. However, only low toxicity was observed in Cocos nucifera, Theobroma cacao L. and Coffea sp. Conclusions: It can be concluded that the obtained results are in accordance with other studies that examined different extracts, indicating that if a sample is non-toxic to Artemia salina, then its effects will also be similar in humans.

Brine Shrimp Toxicity of Essential Oils from Musa spp.

Essential oils of seven Musa spp.’s fruits namely, Musa acuminata colla ‘gros michel’ (PE), Musa acuminata colla ‘lakatan’ (PB), Musa acuminata colla ‘sucrier’ (PM), Musa acuminata × balbisiana ‘horn plantain’ (PT), Musa acuminata × balbisiana colla ‘saba’ (PN), Musa acuminata colla 'inarnibal' (PO) and Musa acuminata colla ‘red’ (PJ) were extracted by hydrodistillation method using Clevenger apparatus. The essential oils were analysed using GC-FID and identified using Kovat Indeces compared with published information. PE gave the highest yields of oils compared to the other species with yield of 0.43% and 0.28% for its peels and flesh, respectively. The most abundant groups present in most of the essential oils are ester and alcohol groups. The brine shrimp toxicity of PT, PM, PN and PO essential oils were tested and showed toxicity against brine shrimp in dose dependent manner. It can be concluded that the essential oils showed some biological activities which may be a potent medicine in curing tumor. This study implies that the presence of ester and alcohol groups are a good marker for the biological activities of plants. Further studies should focus on the potential of the essential oils of Musa spp. as an antitumor medicine.

Influence of bunch bagging on the development of banana Prata (AAB) and prevention of chilling injury in the field

Banana is extremely sensitive to chilling injury (CI). It shows symptoms of peel browning at approximately 12°C and severe symptoms at 6°C. The purpose of this study was to investigate the influence of different bagging materials on development of banana bunch (Musa spp. AAB cv. Prata) and preventing CI in field. The study was carried in Jacupiranga, São Paulo, Brazil, in a completely randomized design in 2 × 9 factorial, in which treatments were two years of formation of bunch and nine bagging materials, with eight replicates. Bagging was performed in the autumn and winter to ensure the occurrence of CI in the field, and the evaluations after harvesting and fruit maturation. The bagging materials consisted of blue transparent polyethylene, white non-woven fabric, white opaque polyethylene, bubble wrap, white laminated non-woven fabric, double paper, blue transparent polyethylene plus kraft paper, blue transparent polyethylene plus white non-woven fabric and non-bagged. In 2013, the bunches of were exposed to 182.02 h of temperatures lower than 12C and 5.25 h of temperatures lower than 5C, while in 2014, only 70.76 h of temperatures lower than 12C was provided. Bunches formed in 2013 had longer exposure periods between flowering and harvest due to the low temperatures, but exhibited higher mass than those formed in 2014. The CI index was only 1.38 in 2013 and 1.00 in 2014 (p<0.05). On the colder days of 2013 and 2014, bagging raised peel temperature 1.91 and 3.17°C, respectively. The bagging material influenced yield, the accumulation of nutrients in fruits and the hue angle of peel. Double paper promoted fruits with more yellow peel.

Morpho-anatomy of the inflorescence of Musa × paradisiaca

Bananas and plantains are herbaceous monocotyledonous plants belonging to the genus Musa, Musaceae, which has a widespread distribution around the world. Various parts of banana plant are commonly used in traditional medicines. Several species of Musa are reported to possess anti-inflammatory, anti-hyperglycemic and antidiabetic properties. This work is aimed at studying the morphological and anatomical characteristics of the inflorescences of Musa×paradisiaca L., that could contribute to the characterization of these species cultivated in Brazil. Plant materials were collected and prepared in accordance with standard optical microscopy techniques. Morphological characterizations were conducted using morphological descriptors for inflorescences, including some descriptors from International Plant Genetic Resources Institute for Musa spp. Microscope slides were prepared using glycol-methacrylate and were stained in toluidine blue. Main features observed for M.×paradisiaca inflorescence were amphistomatic bracts with tetracytic stomata, fiber caps next to the phloem, adaxial and abaxial uniseriate epidermis, and papillose on the abaxial face. Outer tepals have multilayer epidermis and vascular bundles aligned next to the abaxial face. Free tepal has unilayeredepidermis. Anthers are tetrasporangiate and the locules are separated by the septum. Ovary is inferior and trilocular with external unilayered and internal epidermis. The main morpho-anatomical characteristics of inflorescence of Musa×paradisiaca are highlighted in this study, contributing to provide more information about the characterization of this species cultivated in Brazil.

Protoplast isolation and culture from different explants of Musa spp. Cau man

In this paper, the roles of type and concentration of enzymes on protoplast isolation from in vitro leaves, multi-scalps (highly proliferating meristem culture), and young male flower of banana cv. cau man were studied. Respiration rate and content of plant hormones of these materials were analysed. Different techniques were used to culture these protoplasts. The development of protoplasts was observed under fluorescence microscope. The highest yield of protoplast (69.5 x 106 protoplasts / g fresh weight) was obtained from young male flowers after 16 hours treatment with 1.5 % cellulase, 0.25 % pectinase and 0.25 % hemicellulase. The combination of hanging drop cell technique (in 6 days), and carrot feeder layer cells in N6PKM medium supplemented with 0.2 mg/L 2,4- dichlorophenoxyacetic acid (2,4-D), 1 mg/L α- naphthalene acetic acid (NAA), and 0.5 mg/L zeatin are suitable for protoplast development. Protoplasts that were isolated from multi-scalps and young male flowers created the wall and divided when cultured by this method. The development of protoplasts from young male flower began with cell walls creation after 4 days, the cell division was after 6 days, and small colonies formation was after 28 days of culture. The differentiation and physiological activity of cells play an important role on quantity and quality of protoplasts, as on the well as protoplast development.

Plant regeneration, developmental pattern and genetic fidelity of somatic embryogenesis derived Musa spp.

Multiplication of banana cvs. Grand Naine (Musa AAA, Cavendish-sub group) and Rasthali (Musa AAB, Silk-sub group) were attempted through somatic embryogenesis. The influence of position of male flower buds, amino acid supplements in the induction of somatic embryogenesis and field performance of embryogenic cell suspension (ECS) derived banana plants were studied. Differentiated immature male flower buds positioned at 6–8 th bract whorl as explants showed better callus induction and somatic embryogenesis. Supplementation with glutamine at 400 mg L−1 along with 20:20 g L−1sucrose: maltose in maturation media induced a 10-fold increase in somatic embryo formation compared to control. Cotyledonary stage somatic embryos desiccated for 2 h showed higher germination compared to non-desiccated embryos. The plantlets generated were hardened, and the genetic fidelity of the plantlets was confirmed using ISSR marker. To check the field performance of ECS derived plants, plantlets were hardened and planted in the field along with meristem and sucker. During the field growth, these ECS derived plants were morphologically similar to those of control plants. In this experiment, it was observed that ECS derived banana plants displayed normal phenotype as that of plants grown from meristem and sucker. The protocol developed could be useful highly for large-scale micropropagation or genetic manipulation studies in these commercially important banana cultivars.

RAPD Analysis of the Genetic Diversity Among Accessions of Micropropagation Bananas from Indonesia

Molecular Characterization of banana (Musa spp) is very important for the purpose of conservation and improvement of plants. This research was conducted to investigate phylogenetic of Musa spp cultivar namely Cavendish, Barangan, Raja Buluh and Kepok. RAPD analysis was performed on four accessions of Musa spp, originating from West Java, Indonesia. The samples used were taken from the plant result of micropropagation at Tissue Culture laboratory Lebak Bulus, Jakarta, Indonesia. The result of PCR-RAPD visualization produces bands whose size ranges from 200-1500 bp. The primers used were able to amplify four samples clearly. The DNA amplification results show that the four primers can produce 62 polymorphic and monomorphic bands. A total of 30 polymorphic bands is capable of producing on PCR-RAPD process with 48.29%. Primer OPB 3 produces the most polymorphic bands of 10 bands whereas OPB 4 produces only four polymorphic bands. Primer OPB 3 is capable of producing the highest percentage of polymorphic loci that is 55.56%. Dendogram results show that at the coefficient of 0.68 separation occurs in the Raja Buluh with other samples. While in the coefficient of 0.70, the varieties of Kepok shows the separation of Raja Buluh and Cavendish. At the coefficient of 0.90, the Barangan and Cavendish varieties are in the same branching which tools that the two have close phylogenetic. RAPD sequence analysis has provided more information on the inter-species phylogenetic status of these four cultivars of Musa spp.

Differentially expressed genes during the transition from early to late development phases in somatic embryo of banana (Musa spp. AAB group, Silk subgroup) cv. Manzano

A cDNA-sequence-related amplified polymorphism (cDNA-SRAP) approach was used to identify relevant genes expressed at the onset of somatic embryo maturation/desiccation in banana (Musa spp. AAB group, Silk subgroup) cv. Manzano. For this, an embryogenic procedure, starting with cell suspensions, was first improved by including a culture period on a free growth-regulator medium for embryo maturation. This produced an up to 95% germination of the coleoptilar embryos. Gene expression patterns were followed through different stages of the process, including immature male flower explants, embryogenic calli, as well as immature, mature and germinated embryos. A total of 151 differentially expressed transcript-derived fragments (TDFs) were detected, sequenced, resulting in the identification of 71 by their similitude to accessions deposited in different data bases. The participation of four of these genes, putatively involved in the banana somatic embryogenesis, was further analyzed by real-time quantitative PCR (q-PCR). This confirmed their preferential expression at the transition from embryo early development to maturation. Noteworthy, tryptophan aminotransferase relate 2 (TAR2), which is involved in the indole-3-pyruvic acid dependent auxin biosynthesis, corresponded to one of the upregulated four genes, suggesting the requirement of this growth regulator at the transition stage. This study opens the path for future in-depth studies of molecular and biochemical events occurring during in vitro somatic embryogenesis in edible bananas.

Screening for Potential Plant Growth-Promoting Rhizobacteria (PGPR) Associated with Five Musa spp. Cultivars in SOCCSKSARGEN, Philippines

Rhizospheric bacteria (PGPR) associated with 5 banana cultivars planted in SOCCSKSARGEN were studied. Microbial population in newly established and old plantation was compared. Bacteria were purified and their beneficial characteristics were determined. This study was able to collect one hundred twenty (120) bacterial isolates, 20 (17%) of which were nitrogen-fixers, nineteen (19/20) were phosphate solubilizers and seventeen (17/20) were IAA producers. From this study, five bacterial isolates coded PE05, RS10, PE11, PE13, and PE18 were found positive for nitrogen fixation, phosphate solubilization and IAA production which may be further evaluated for their potential application in the formulation of biofertilizers for banana cultivation.
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Survey on Ethnobotanic Value of Banana (Musa spp; Musaceae) in Bali Province, Indonesia

Bali, one of Indonesia island, is a region inhabited by a large number and varied banana (Musa spp; Musaceae). Many varieties of banana have been utilized by local peoples since long time ago as traditional medicine, edible material, used in traditional ceremony and others. However, information regarding the knowledge on ethnobotany of banana in Bali remains scattered and is not documented well. The purpose of this study was to evaluate and document the ethnobotanic values of bananas in Bali. Ethnobotanic data was collected through focus group discussion (FGD), surveys and interviews from 9 study sites (1 city and 8 regencies) with one or two villages represented each site. Ethnobotanical value of banana was determined by Local User’s Value Index (LUVI) with Pebble Distribution Method (PDM). Subsequently, data obtained was analysed using simple statistic description. Results showed that as many as 44 varieties of banana in Bali were documented. Local peoples have been utilizing banana in their daily life for ritual as indicated by higher LUVI (0.4867), followed by food (0.3), medicine (0.1533), and other (0.06). On the basis of testimony of respondents, indigenous knowledge of peoples in Bali about banana is vertically transmitted from parents to their children (98%). This study provided a valuable information of how the local peoples manage and conserve the banana and its nature.

Correlation between repassivation kinetics and pitting potential of 316L stainless steel in the presence of green inhibitors

PurposeThis paper aims to investigate the stability of passive oxide film formed on the surface of 316L stainless steel in 3.5 Wt.% NaCl in the presence of two environmentally non-toxic inhibitors, i.e. leaf extracts of Musa spp. (MS) and Jatropha curcas (JC).Design/methodology/approachCurrent transients and potentiodynamic polarization curves were used to explain the stability of the passive film on Current transients and potentiodynamic polarization curves were used to explain the stability of the passive film on 316L stainless steel at both ambient temperature (25 °C) and 70 °C. For the potentiostatic tests, the coupons underwent cathodic stripping to remove the native oxide on their surfaces at −850 mV for 600 s, and a potential of 50 mV was imposed to observe the repassivation for 200 s. For the potentiodynamic tests, the pitting potential measured at 100 μA/cm2, corrosion potential and cathodic current density were obtained for analysis.FindingsThe current transients perfectly fitted into the exponential decay curve; i = is + ipeak exp(−t/τ), where the decay constant, τ measures the repassivating speed and extent to which the newly formed film heals and stabilizes. The current transients showed that MS and JC help in the repassivating process, especially at 300 ppm and 200 ppm, respectively, both at the lower temperature. The potentiodynamic curves mostly correlated with the current transients except for the hybrid inhibitor. The inhibitors increased the pitting potentials at concentrations that are correlated to their scanning electron micrograph images.Research limitations/implicationsBecause they are cheap and environmentally friendly, plant extracts that are proven corrosion inhibitors could be used to aid the formation of passive film on passive alloys in not-so-aggressive environments.Practical implicationsBoth MS and JC improve the film stability mostly at intermediate concentrations of 200 and 300 ppm, respectively, at ambient temperature and 70° C.Social implicationsUsing leaf extracts of plants as green inhibitors is considered an environmentally friendly engineering solution.Originality/valueThe leaf extracts are a convenient resource of green inhibitors because their plants are readily available or could be easily naturalized, the processing technique to obtain the extracts is very cheap and the inhibitors are environmentally friendly. In addition, cathodic stripping exposes a relatively larger surface area than that obtained using the most common forms of depassivation; hence, the efficiency of the inhibitor in aiding the formation of the new oxide film to cover the bare surface would be better measured. There is very lean research data on the combined use of green inhibitors and cathodic stripping to study repassivating kinetics of passive alloys.

English

Soil degradation and desertification pose a major threat to agricultural production in sub-Saharan Africa. The influence of cropping systems which had been established on selected physical and chemical properties of soil were investigated in Akinyode-Okinni community in Egbedore Local Government Area (LGA) of Osun State, Nigeria. The cropping systems included agri-silviculture (SCM), silvi-pasture (SPC), agri-horti-silviculture (PAH) and agroforestry (AFT) selected from existing farms in the community. The selected plots had cocoa (Theobroma cacao), oil palm (Elais guineensis) and kola-nut (Kola nitida) as permanent crops; coco-yam (Coco nucifera), guinea grass (Panicum maximum), plantain (Musa spp), maize (Zea mays), and cassava (Manihot utilissima) were the annual crops. The experiment was carried out for two cropping seasons. Results showed that in the AFT system bulk density (BD) decreased slightly from 1.22 to 1.16 g/cm3 in the top soil and from 1.18 to 1.09 g/cm3 in the subsoil after two seasons of crop growth. The pH varied between 6.40 and 7.05 in the first season and between 7.05 and 7.29 after two seasons. On average, the topsoil contained more organic carbon (OC) in the SPC (38 g kg-1) and SCM (36 g kg-1) systems than in the PAH and AFT systems. Similarly, the total phosphorus content was higher in the topsoil of SPC and SCM systems than in the other systems. There was a slight reduction in soil acidity and no significant changes occurred in the concentrations of exchangeable bases after two cropping seasons. Conclusively, these cropping systems have the potential to reduce soil deterioration and thus, further studies to develop appropriate management strategies are necessary. Key words: Cropping systems, exchangeable bases, organic carbon, silviculture, soil degradation. &nbsp