Effects of different treatments on seed germination and breaking seed dormancy of Prosopis koelziana and Prosopis Juliflora

For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for 10 and 15 min, sandy paper, hot water for 5 and 10 min, potasium nitrate 0.1%, gibberellic acid at 250 mg·L^-1 and 500 mg·L^-1 and combinational treatment of scarification with gibberellic acid of 250 mg·L^-1 and 500 mg·L^-1. The results show that scarifications with sandy paper and sulfuric acids 98% were the most effective treatments on breaking seed dormancy and seed germination induction. Scarification with sulfuric acid 98% for 15 min was the best treatment. According to the positive effect of scarification and lack of reaction of seeds against KNO3 and gibberellic acid, the kind of seed dormancy was determined as exogenous.

Study of the distribution profile of piperidine alkaloids in various parts of Prosopis juliflora by the application of Direct Analysis in Real Time Mass Spectrometry(DART-MS)

Direct Analysis in Real Time Mass Spectrometry(DART-MS)was applied to identify and study the distribution profile of piperidine alkaloids in different parts of Prosopis juliflora,without isolation and separation of the compounds by standard chromatographic techniques.With the help of DART-MS,chemical fingerprint of raw plant parts were generated,which revealed the presence of piperidine alkaloids in leaf,pod and flower.A comparative study of the distribution pattern,showed variation in the presence and distribution of these alkaloids in various parts of P.juliflora.The leaves and pod displayed the largest alkaloid pattern with a total of 12 different alkaloids in each part,whereas only 4 alkaloids were present in flower.Alkaloids:julifloridine,prosopine,prosopinine and prosafrinine were ubiquitously distributed in all the alkaloid rich plant parts.Juliprosopine was pre-eminet alkaloid in leaf,whereas pod and flower displayed copious amounts of julifloridine.

Relationship between Prosopis juliflora invasion and livelihood diversification in the South Afar region,Northeast Ethiopia

This study assessed the effects of Prosopis juliflora invasion on livelihood diversification and evaluated the determinants of livelihood diversification in two districts in the South Afar region of Northeast Ethiopia.Using random sampling method,154 households and 2 focus groups composed of 10 individuals were selected from four sites in the two districts.The relationship between P.juliflora invasion and incomes obtained from P.juliflora varied across the study sites.In Awash Fentale District and Amibara District,11.0%and 3.2%of households,respectively,earned income from P.juliflora charcoal production.In total,14.3%of households were involved in charcoal production.In addition,19.9%of households earned income from selling P.juliflora pods and wood materials in the two districts.With the exception of income from P.juliflora charcoal production,the sex of households did not affect incomes from other livelihood activities.Moreover,household educational attainment significantly affected income obtained from vegetables,fruits,and cereal crops.Male householders were engaged in more diverse livelihood activities than female householders.Reversing the severe invasion of P.juliflora on grazing and woodlands in the region is advisable through integrated natural resources,pastoralist participation,and multidisciplinary research strategies.

The invasion of Prosopis juliflora and Afar pastoral livelihoods in the Middle Awash area of Ethiopia

Introduction:An evergreen shrub,Prosopis juliflora is one of the most invasive species in arid and semi-arid areas.Since its introduction to the Middle Awash area of Ethiopia,it has invaded a huge acreage of grass-and rangelands which are life-supporting unit for Afar pastoralists.Methods:Survey,using group discussion and questionnaire,was made to study the effect of P.juliflora invasion on Afar pastoral livelihoods.The obtained data were analyzed using Wilcoxon signed-rank test,chi-square analysis,and logistic regression.Results:According to the result,84%of the total surveyed households rated P.juliflora as undesirable species even though the bush was often used for fuelwood,fencing homesteads,and barn and house construction.Invasion of P.juliflora was also blamed to limit transhumance,occupying settlement areas and affecting multipurpose trees/bushes and grass availability.All these effects put pressure on the livestock assets causing about 80%livestock loss,testing the pastoral livelihoods heavily.Each household,on average,lost 6.5 small stock and 7 cattle during the past 10 years due to health hazards caused by P.juliflora pod.Consequently,P.juliflora as a source of income was considered by a quarter of the surveyed pastoral households,with the age of a household head and change in livestock asset being influential variables in decision-making.Conclusions:In sum,P.juliflora invasion has made livestock rearing extremely difficult which raised pastoralists’ecological vulnerability in the fragile ecosystem they possess.

Species Distribution Modelling performance and its implication for Sentinel-2-based prediction of invasive Prosopis juliflora in lower Awash River basin, Ethiopia

Background:Species Distribution Modelling(SDM)coupled with freely available multispectral imagery from Sentinel-2(S2)satellite provides an immense contribution in monitoring invasive species.However,attempts to evaluate the performances of SDMs using S2 spectral bands and S2 Radiometric Indices(S2-RIs)and biophysical variables,in particular,were limited.Hence,this study aimed at evaluating the performance of six commonly used SDMs and one ensemble model for S2-based variables in modelling the current distribution of Prosopis juliflora in the lower Awash River basin,Ethiopia.Thirty-five variables were computed from Sentinel-2B level-2A,and out of the variables,twelve significant variables were selected using Variable Inflation Factor(VIF).A total of 680 presence and absence data were collected to train and validate variables using the tenfold bootstrap replication approach in the R software“sdm”package.The performance of the models was evaluated using sensitivity,specificity,True Skill Statistics(TSS),kappa coefficient,area under the curve(AUC),and correlation.Results:Our findings demonstrated that except bioclim all machine learning and regression models provided successful prediction.Among the tested models,Random Forest(RF)performed better with 93%TSS and 99%AUC followed by Boosted Regression Trees(BRT),ensemble,Generalized Additive Model(GAM),Support Vector Machine(SVM),and Generalized Linear Model(GLM)in decreasing order.The relative influence of vegetation indices was the highest followed by soil indices,biophysical variables,and water indices in decreasing order.According to RF prediction,16.14%(1553.5 km^(2))of the study area was invaded by the alien species.Conclusions:Our results highlighted that S2-RIs and biophysical variables combined with machine learning and regression models have a higher capacity to model invasive species distribution.Besides,the use of machine learning algorithms such as RF algorithm is highly essential for remote sensing-based invasive SDM.

Effects of native and invasive Prosopis species on topsoil physiochemical properties in an arid riparian forest of Hormozgan Province,Iran

Biological invasions can alter soil properties within the range of their introduced,leading to impacts on ecosystem services,ecosystem functions,and biodiversity.To better understand the impacts of biological invasions on soil,we compared topsoil physiochemical properties at sites with invasive alien tree species(Prosopis juliflora),native tree species(Prosopis cineraria,Acacia tortilis,and Acacia ehrenbergiana),and mixed tree species in Hormozgan Province of Iran in May 2018.In this study,we collected 40 soil samples at a depth of 10 cm under single tree species,including P.juliflora,P.cineraria,A.tortilis,and A.ehrenbergiana,as well as under mixed tree species.The results showed that organic matter,moisture,potassium,calcium,nitrogen,and magnesium in topsoil at sites with A.tortilis and A.ehrenbergiana growing in combination with P.cineraria were higher than that at sites where P.juliflora was present(P<0.05).Sodium at sites with A.tortilis and A.ehrenbergiana growing in combination with P.cineraria and P.juliflora was lower as compared to that at sites with just A.tortilis and A.ehrenbergiana.Electrical conductivity was lower at sites with A.tortilis and A.ehrenbergiana growing in combination with P.cineraria,and it was higher at sites with mixed Acacia and P.juliflora trees.Based on the generally more positive effect of native Acacia and P.cineraria on topsoil physiochemical properties as compared to the P.julifora,afforestation with native tree species is preferable for soil restoration.In addition,due to the negative effects of P.julifora on soil properties,P.julifora spread should be better managed.

Potential of biocontrol agents against Ganoderma lucidum causing basal stem rot in mesquite(Prosopis cineraria)in arid regions of India

This study investigates the potential of native biocontrol agents(BCAs)as controls against Ganoderma lucidum causing root rot mortality in Indian mesquite.The disease is prevalent in sandy soils where trees grow under rainfed conditions.In addition,a beetle namely A canthophorus serraticornis damages the roots,resulting in increasing vulnerability of the host thereby allowing easy of the pathogen.In dual culture tests,Ganoderma infected cowpea root bit experiment and compatibility with insecticides revealed that the three BCAs(Trichoderma longibrachiatum,T.harzianum,and Aspergillus nidulans)significantly inhibited G.lucidum mycelial growth.The highest mycelial growth inhibition(47.6%)was recorded after 96 h followed by 39.8%and 29.3%at 72 and 48 h,respectively,by T.longibrachium.Cell free filtrates of T.longibrachiatum,T.harzianum,and A.nidulans were superior in inhibiting mycelium growth.A low concentration(3 ml)of T.longibrachiatum was more effective in inhibiting mycelium growth compared to other BCAs.Both P rosopis julifl ora compost and onion residue compost amendments as food substrates favored the growth of these BCAs,which ultimately reduced the viability of Ganoderma-colonized root bits of cowpea.Studies on compatibility between insecticides and BCAs suggests that T.longibrachiatum,harzianum and A.nidulans can be combined with phorate or chloropyriphos(both organophosphates)at variable concentrations if amended together for partially infected trees,or as a prophylactic measure in healthy trees.These studies demonstrate that there is considerable opportunity for using native BCAs against G.lucidum in managing root rot disease.

Mathematical Modeling and Determination of Effective Diffusivity of Mesquite during Convective Drying

The mesquite pods have a high nutritional value, being a rich source of sugars, proteins, minerals and fibers that can be used as a raw material for the development of a number of food products and technological innovations. The objective of this work was to study the drying kinetics of mesquite pods in a thin layer, 20 mm length and determine the effective diffusion coefficient by adjusting mathematical models that were based on heat transfer and mass fundamentals. For the experiments, we used mature mesquite, with 20% water content (b.u). Drying experiments were performed using temperatures of 50°C, 60°C, 70°C and 80°C with drying air speed of 2 m•s-1. It was used a convective dryer with fixed bed and upflow air. Mathematical models of Fick, Page, Cavalcanti-Mata, Two Exponential Terms and Henderson & Pabis were used to adjust the experimental data. To calculate the effective diffusivity, flat plate geometry with sample thickness of 6.5 mm was used. Based on the results obtained, it was concluded that the loss of water from mesquite occurred during the drying period in decreasing rate;and with increasing drying temperature, total process time was reduced. The diffusion coefficient increased by increasing drying temperature. Mathematical models including theoretical (Fick), semi-theoretical (Page and Cavalcanti-Mata) and empirical (Two Exponential Terms) models satisfactorily explain the experimental data of drying mesquite.

Contrasting plant growth performance of invasive polyploid and native diploid Prosopis is mediated by the soil bacterial community

Background Soil microbial communities affect above-ground plant diversity and community composition by influencing plant growth performance.Several studies have tested the effect of soil bacterial microbiome on growth performance of native and invasive plants,but the influence of specific bacterial isolates has not been investigated.Here,we investigated the effects of soil bacterial exclusion by soil sterilization and by inoculation of Streptomyces rhizobacterial isolates on the growth performance of native and invasive Prosopis congeners.Results Plant growth performance of invasive P.juliflora was significantly reduced when grown in sterilized soils,whereas native P.cineraria showed enhanced growth performance in the sterilized soils.When grown in the soil inoculated with the specific Streptomyces isolate from P.juliflora(PJ1),the growth performance of invasive P.juliflora was significantly enhanced while that of native P.cineraria seedlings was significantly reduced.However,inoculation of P.cineraria and P.juliflora seedlings with Streptomyces isolate from the rhizosphere of native P.cineraria(PC1)had no significant effect on the growth performances either of P.juliflora or P.cineraria.Conclusion Our study reveals that invasive P.juliflora experiences positive feedback from the non-native soil bacterial community,while the native P.cineraria experiences negative feedback from its soil bacterial community.Our results provide fresh experimental evidence for the enemy release hypothesis,and further our understanding of the contrasting growth-promoting effects of differentially recruited microbial species belonging to the same genus(Streptomyces)in the rhizospheres of alien invasive and native plants.