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...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.展开更多
This study was aimed to determine the extent to which Prosopis species had invaded four settlements (Bokspits, Rappelspan, Vaalhoek and Struizendam) located in the Kgalagadi Desert south west of Botswana, investigate ...This study was aimed to determine the extent to which Prosopis species had invaded four settlements (Bokspits, Rappelspan, Vaalhoek and Struizendam) located in the Kgalagadi Desert south west of Botswana, investigate the perceptions of the communities about the existence of the species in their environment and assess possible control options for the spread of Prosopis plants in the area. Prosopis plants were sampled in 42 quadrats of 625 m2 along a 70 km Prosopis invasion gradient from Struizendam to Rappelspan. Using the Global Positioning System (GPS), the locations of all quadrats were established. The distribution map of Prosopis plants was produced using ArcGIS 9.2 (ESRI Inc.). Questionnaire survey and focused group discussions were used to collect data on the perceptions of rural communities about the species. A total of 342 respondents comprising 139 males and 203 females were interviewed, and four focussed group discussions were conducted. The results indicated that the invasion of Prosopis species was prominent in and around settlements suggesting that anthropogenic activities had a significant role in the spread of Prosopis plants in the area. The perceptions of rural communities about Prosopis plants appeared to be moulded by the impacts of the plants on their livelihoods as well as their micro-economic status. The respondents (71.30%) expressed the view that the invasion of Prosopis species negatively affected the livelihoods of the communities in the study area. They identified eradication as the preferred method of controlling the spread of Prosopis plants. On the contrary, this study recommended the integrated environmental management paradigm as the best options for the control of the spread of Prosopis plants in the area.展开更多
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 invasion...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.展开更多
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 innov...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<sup>-1</sup>. 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.展开更多
Most legumes and oil bean seeds used in condiment manufacture in Africa are inedible by nature. They contain antinutritional elements such indigestible oligosaccharides and phytate. Fermentation affects desired altera...Most legumes and oil bean seeds used in condiment manufacture in Africa are inedible by nature. They contain antinutritional elements such indigestible oligosaccharides and phytate. Fermentation affects desired alterations by lowering anti-nutritional components and enhancing digestibility. Okpeye is a traditional West African seasoning prepared from Prosopis africana seed solid substrate fermentation. Many homes consider it as a family business because the preparation follows a passed-down habit from previous generations as an inexpensive source of plant protein. However, natural nature of the fermentation process raises concerns about the consistency, quality, and safety of the finished product. Because the seasoning is created on a small scale with less sophisticated equipment and manufacturing procedures, there are concerns about microbial safety. Thus, fermentation process and the range of microbial composition involved in Prosopis africana okpeye production were evaluated in this review. Potential spoilage agents, as well as biochemical and nutritional changes occurring during production of okpeye are gaining interest among researcher. This review highlights information that can help in developing starter cultures in a controlled fermentation process that ensures quality, longer shelf life, and microbiological safety.展开更多
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...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.展开更多
Prosopis laevigata and Opuntia ficus-indica grow in arid and semiarid regions of Mexico and other countries. Both produce biopolymers with interesting characteristics from the rheological point of view as well as beca...Prosopis laevigata and Opuntia ficus-indica grow in arid and semiarid regions of Mexico and other countries. Both produce biopolymers with interesting characteristics from the rheological point of view as well as because of their coagulating-flocculating capabilities. Prosopis produce galactomannans inside the endosperm, very similar to those found in guar, locust bean, and tara gums. Opuntia sp. produces mucilage that contains polygalacturonic acid and five neutral sugars. Prosopis seed gum has not been proposed to be used as coagulant-flocculant before. In the case of Opuntia mucilage, some authors have suggested its use in the treatment of waters, using either the mucilage or the whole cladode powder. The use of these products in the treatment of municipal or even industrial wastewaters could give rise to diverse benefits. From the environmental point of view, treated waters with neither Fe nor Al, nor synthetic polymers would be obtained (with less toxicity risk). Besides, the produced sludges would be smaller in amount, with better biodegradability, and lower metals content. From the economical point of view, the use of these biopolymers would give an added value to the Opuntia and Prosopis culture in Mexico, helping small communities to enhance their incomes by producing environmental-friendly products. This work shows that both Prosopis galactomannan and Opuntia mucilage can be used to treat municipal wastewaters with an initial organic charge of about 827 mg/L as COD by the coagulation-flocculation process, with COD removals for the mesquite seed gum of up to 90% (pH 10, dose of 75 mg/L) and of 60% (pH 7, doses of 50 and 150 mg/L). In the case of mucilage, 65% of the initial COD was removed at pH 10 (dose of 50 mg/L). These figures are very promising for the treatment of wastewaters, with environmental-friendly products.展开更多
Prosopis farcta, a plant belongs to the mimosoideae, is characterized by a very wide spectrum of various bioactive and medical constituents. Vitexin, the marker flavonoid found in Prosopis, has potent and broad antitu...Prosopis farcta, a plant belongs to the mimosoideae, is characterized by a very wide spectrum of various bioactive and medical constituents. Vitexin, the marker flavonoid found in Prosopis, has potent and broad antitumour efficacy in preclinical models. Many studies had been done for the isolation of flavonoids (vitexin) by completely different chromatographically methodology. During this study, vitexin was isolated from Prosopis farcta by 6 different extraction methods in which parameters as the type, concentration and pH of the extracting solvents considered. Among different solvent systems used, methanol-water (40%, containing acetic acid 0.5%) was found to be the best solvent generating the highest yield (0.554 mg·g-1 DW) from Prosopis leaves. The present work suggests an efficient method for estimation the greatest content of vitexin analyzed by HPLC technique and introduces Prosopis farcta as a suitable source of this flavonoid with several pharmacological properties.展开更多
Drastic changes have occurred in Siti zone rangeland over nearly the last three decades, due to rapid land conversion dynamics in the area. In the zone, the land-use change over time and space and temporal trends rang...Drastic changes have occurred in Siti zone rangeland over nearly the last three decades, due to rapid land conversion dynamics in the area. In the zone, the land-use change over time and space and temporal trends rangeland condition have never been studied. This study analyzed land use and land cover (LULC) change dynamics since the 1980s. Three dates, 1985, 2001 and 2017, Landsat images were used for classification and analysis of the various LULC. The three images were geo-referenced, re-sampled and processed for classification, using the maximum likelihood classifier algorithm. Moreover, field observations and information from local people were used for triangulation to patterns LULC dynamics. From 1985 to 2017, the general trend observed in the land use/cover change in the rangeland resources in the study districts implies a loss of grassland cover was compensated by an increase in cultivated areas, settlement and shrub/bush land cover. Moreover, the encroachments of invasive plant, Prosopis, settlement and the promotion of cultivation to pastoral way of livelihood have exacerbated the decline of rangeland cover. The study findings have shown important changes in the LULC patterns in the north-eastern Somali rangelands of eastern Ethiopia. These trends are certainly the characteristics of a pastoral way of life turn to settlement. This suggests that major changes in the socio-ecological driving forces affecting landscape dynamics have occurred in the last three decades or so.展开更多
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...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.展开更多
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...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.展开更多
The aim of this research was to investigate the interactions between Prosopis plants and soils in the Kalahari area, south west of Botswana. The underlying assumptions of the research were that Prosopis plants signifi...The aim of this research was to investigate the interactions between Prosopis plants and soils in the Kalahari area, south west of Botswana. The underlying assumptions of the research were that Prosopis plants significantly enhanced the nutrient content and improved the condition of soils in the study area, and that the height and canopy size of Prosopis plants affected the interactions between Prosopis plants and the soils. Firstly, soil samples were collected under 42 randomly selected Prosopis plant canopies and in the spaces between Prosopis plant canopies at the depth of 0 -20 cmand 60 –80 cm. Secondly, soil samples were collected under 45 randomly selected Prosopis plant canopies of three different categories of height and canopy size at the depth of 0 -10 cm. The soil samples were analysed for soil organic carbon, pH, total nitrogen (N), electrical conductivity (EC), calcium (Ca), sodium (Na), potassium (K), and magnesium (Mg). Soil collected under Prosopis plant canopies and in the spaces between Prosopis plant canopies showed statistically significant difference in the soil organic carbon content (F = 2.68, P = 0.05, α = 0.05), pH (F = 44.81, P α = 0.05) and electrical conductivity (EC) (F = 3.75, P = 0.01, α = 0.05). Statistically significant difference was also observed in the comparison of soils existing under Classes 1, 2 and 3 Prosopis plant canopies in relation to pH and EC (F = 6.56, P = 0.01 and F = 4.77, P = 0.01 respectively at α = 0.05). Therefore, it was concluded that the fundamental assumptions of the study were valid.展开更多
The morphological variability of Prosopis africana in its natural range (which includes three climate zones: Guinean zone, Sudano-Guinean zone and Sudanese zone) of Benin was studied on the basis of forest inventory c...The morphological variability of Prosopis africana in its natural range (which includes three climate zones: Guinean zone, Sudano-Guinean zone and Sudanese zone) of Benin was studied on the basis of forest inventory carried out in three different vegetation types (savannah, fallow and field). The data recorded in 139 plots of 1000 m2 each related to the diameter at breast height (1.3 m over the ground level), the bole height, the height to the first branch, crown height, the crown diameter, number of branches on each individual tree. In these plots, 143 sheets were used to determine the length of leaf, the pinna length, leaflets’ length, numbers of pinna, the number of leaflets, and the stalk diameter. In addition, 735 cloves were measured to determine the fruit pods’ diameter, pod length, the total fruit weight and number of seeds per fruit, the seed length, the weight of a seed, and pulp weight. Analysis of variance components shows that the variability of Prosopis is generally greater among individuals than within vegetation types and climatic zones. Discriminant analysis showed that of the 19 morphometric characters seven (7) in the vegetation types and twelve (12) in climate zones revealed a statistically significant discriminating pattern r (prob. P. africana trees measured, 10 morphogroups were depicted on the basis of 19 morphometric characteristics (R2 = 52.6%).展开更多
An experiment was initiated in 2008 to evaluate the impact of irrigation regimes on germination and growth patterns of seedlings of Prosopis cineraria in the arid areas of Thar, India. Seeds collected from dried pods ...An experiment was initiated in 2008 to evaluate the impact of irrigation regimes on germination and growth patterns of seedlings of Prosopis cineraria in the arid areas of Thar, India. Seeds collected from dried pods of P cineraria were sown in polybags placed in nursery beds. Different irrigation regimes were provided to different beds and data regarding germination and growth were recorded to study natural regeneration. The study revealed that irrigation regimes significantly affected the germination and growth of P cineraria under nursery conditions. The germination rate declined as the irrigation regime shifted from a daily to a fortnightly ba- sis. Height of the seedlings also declined with a decrease in the intensity of irrigation. Thus, it can be concluded that germination and growth of seedlings of P cineraria under nursery conditions can be enhanced by providing irrigation at regular intervals.展开更多
Arbuscular mycorrhizal （AM） fungi associated with Prosopis cineraria （Khejri） were assessed for their qualitative and quantitative distribution from eight districts of Rajasthan. A total of three species of Acaulo...Arbuscular mycorrhizal （AM） fungi associated with Prosopis cineraria （Khejri） were assessed for their qualitative and quantitative distribution from eight districts of Rajasthan. A total of three species of Acaulospora, one species of Entrophospora, two species of Gigaspora, twenty-one species of Glomus, seven species of Sclerocystis and three species of Scutellospora were recorded. A high diversity of AM fungi was observed and it varied at different study sites. Among these six genera, Glomus occurred most frequently. Glomus fasciculatum, Glomus aggregatum, and Glomus mosseae were found to be the most predominant AM fungi in infecting Prosopis cineraria. Acaulospora, G. fasciculatum, Sclerocystis was found in all the fields studied, while Scutellospora species were found only in few sites. A maximum of thirty-six AM fungal species were isolated and identified from Jodhpur, whereas only thirteen species were found from Jaisalmer. Spores of Glomusfasciculatum were found to be most abundant under Prosopis cineraria.展开更多
This study investigated the antifungal activity of leaf extracts of Prosopis africana and Anacardium occidentale against Macrophomina phaseolina, the causal agent of root rot of Sesamum indicum L. Phytochemical analys...This study investigated the antifungal activity of leaf extracts of Prosopis africana and Anacardium occidentale against Macrophomina phaseolina, the causal agent of root rot of Sesamum indicum L. Phytochemical analysis of the two plants showed the presence of alkaloids, saponins, tannins, flavonoids and anthraquinones in petroleum ether, ethyl acetate, methanol and water extracts. The effectiveness of the two medicinal plants viz: P. africana and A. occidentale was tested against the causative agent of root rot of Sesamum indicum L. The effect of plant leaf extracts on mycelia growth of the test organism shows that both P. africana and A. anacardium reduced the mycelia growth significantly as compared to the control (plate, 2, 3, 4). The antifungal property of P. africana and A. occidentale makes these plants of potential interest for the control of the fungi Macrophomina phaseolina.展开更多
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 evalua...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.展开更多
Degradation processes affect a vast area of arid and semi-arid lands around the world and damage the environment and people′s health. Degradation processes are driven by human productive activities that cause direct ...Degradation processes affect a vast area of arid and semi-arid lands around the world and damage the environment and people′s health. Degradation processes are driven by human productive activities that cause direct and indirect effects on natural resources, such as species extinction at regional scale, reduction and elimination of vegetation cover, soil erosion, etc. In this context, ecological rehabilitation is an important tool to recover key aspects of the degraded ecosystem. Rehabilitation trials rely on the use of native plant species with characteristics that allow them to obtain high survival and growth rates. The aim of this work was to assess the survival and growth of native woody species in degraded areas of northeastern Patagonia and relate them to plant functional traits and environmental variables. We observed high early and late survival rates, and growth rates in Prosopis flexuosa DC. var. depressa F.A. Roig and Schinus johnstonii F.A. Barkley, and low values in Condalia microphylla Cav. and Geoffroea decorticans(Gillies ex Hook. & Arn.) Burkart. Early survival rates were positively associated with specific leaf area(SLA) and precipitation, but negatively associated with wood density, the maximum mean temperature of the warmest month and the minimum mean temperature of the coldest month. Late survival rates were positively associated with SLA and soil organic matter, but negatively associated with plant height and precipitation. The temperature had a positive effect on late survival rates once the plants overcame the critical period of the first summer after they were transplanted to the field. Prosopis flexuosa and S. johnstonii were the most successful species in our study. This could be due to their functional traits that allow these species to acclimatize to the local environment. Further research should focus on C. microphylla and G. decorticans to determine how they relate to productive conditions, acclimation to environmental stress, auto-ecology and potential use in ecological rehabilit展开更多
Plants are able to influence their growing environment by changing biotic and abiotic soil conditions.These soil conditions in turn can influence plant growth conditions,which is called plant–soil feedback.Plant–soi...Plants are able to influence their growing environment by changing biotic and abiotic soil conditions.These soil conditions in turn can influence plant growth conditions,which is called plant–soil feedback.Plant–soil feedback is known to be operative in a wide variety of ecosystems ranging from temperate grasslands to tropical rain forests.However,little is known about how it operates in arid environments.We examined the role of plant–soil feedbacks on tree seedling growth in relation to water availability as occurring in arid ecosystems along the west coast of South America.Methods In a two-phased greenhouse experiment,we compared plant–soil feedback effects under three water levels(no water,10%gravimetric moisture and 15%gravimetric moisture).We used sterilized soil inoculated with soil collected from northwest Peru(Prosopis pallida forests)and from two sites in north-central Chile(Prosopis chilensis forest and scrublands without P.chilensis).Important Findings Plant–soil feedbacks differed between plant species and soil origins,but water availability did not influence the feedback effects.Plant–soil feedbacks differed in direction and strength in the three soil origins studied.Plant–soil feedbacks of plants grown in Peruvian forest soil were negative for leaf biomass and positive for root length.In contrast,feedbacks were neutral for plants growing in Chilean scrubland soil and positive for leaf biomass for those growing in Chilean forest soil.Our results show that under arid conditions,effects of plant–soil feedback depend upon context.Moreover,the results suggest that plant–soil feedback can influence trade-offs between root growth and leaf biomass investment and as such that feedback interactions between plants and soil biota can make plants either more tolerant or vulnerable to droughts.Based on dissecting plant–soil feedbacks into aboveground and belowground tissue responses,we conclude that plant–soil feedback can enhance plant colonization in some arid ecosystems by promoting root 展开更多
文摘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.
文摘This study was aimed to determine the extent to which Prosopis species had invaded four settlements (Bokspits, Rappelspan, Vaalhoek and Struizendam) located in the Kgalagadi Desert south west of Botswana, investigate the perceptions of the communities about the existence of the species in their environment and assess possible control options for the spread of Prosopis plants in the area. Prosopis plants were sampled in 42 quadrats of 625 m2 along a 70 km Prosopis invasion gradient from Struizendam to Rappelspan. Using the Global Positioning System (GPS), the locations of all quadrats were established. The distribution map of Prosopis plants was produced using ArcGIS 9.2 (ESRI Inc.). Questionnaire survey and focused group discussions were used to collect data on the perceptions of rural communities about the species. A total of 342 respondents comprising 139 males and 203 females were interviewed, and four focussed group discussions were conducted. The results indicated that the invasion of Prosopis species was prominent in and around settlements suggesting that anthropogenic activities had a significant role in the spread of Prosopis plants in the area. The perceptions of rural communities about Prosopis plants appeared to be moulded by the impacts of the plants on their livelihoods as well as their micro-economic status. The respondents (71.30%) expressed the view that the invasion of Prosopis species negatively affected the livelihoods of the communities in the study area. They identified eradication as the preferred method of controlling the spread of Prosopis plants. On the contrary, this study recommended the integrated environmental management paradigm as the best options for the control of the spread of Prosopis plants in the area.
文摘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.
文摘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<sup>-1</sup>. 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.
文摘Most legumes and oil bean seeds used in condiment manufacture in Africa are inedible by nature. They contain antinutritional elements such indigestible oligosaccharides and phytate. Fermentation affects desired alterations by lowering anti-nutritional components and enhancing digestibility. Okpeye is a traditional West African seasoning prepared from Prosopis africana seed solid substrate fermentation. Many homes consider it as a family business because the preparation follows a passed-down habit from previous generations as an inexpensive source of plant protein. However, natural nature of the fermentation process raises concerns about the consistency, quality, and safety of the finished product. Because the seasoning is created on a small scale with less sophisticated equipment and manufacturing procedures, there are concerns about microbial safety. Thus, fermentation process and the range of microbial composition involved in Prosopis africana okpeye production were evaluated in this review. Potential spoilage agents, as well as biochemical and nutritional changes occurring during production of okpeye are gaining interest among researcher. This review highlights information that can help in developing starter cultures in a controlled fermentation process that ensures quality, longer shelf life, and microbiological safety.
基金supported by Faculty Research Grant of the Institution of Eminence,University of Delhi provided to MKPThis work received grant specifically from Department of Biotechnology(DBT/2015/UOD/358),Government of India,provided to RK+2 种基金Financial support received from Council for Scientific and Industrial Research(CSIR)(09/045(1601)/2018/EMR-I)provided to MS is acknowledgedInfrastructure facilities funded by DST-FIST,UGC-SAP(DRS)and TEQIP and AICTE-MODROBS are acknowledgedThe financial assistance of IoE FRP Grant to MKP is gratefully acknowledged.
文摘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.
文摘Prosopis laevigata and Opuntia ficus-indica grow in arid and semiarid regions of Mexico and other countries. Both produce biopolymers with interesting characteristics from the rheological point of view as well as because of their coagulating-flocculating capabilities. Prosopis produce galactomannans inside the endosperm, very similar to those found in guar, locust bean, and tara gums. Opuntia sp. produces mucilage that contains polygalacturonic acid and five neutral sugars. Prosopis seed gum has not been proposed to be used as coagulant-flocculant before. In the case of Opuntia mucilage, some authors have suggested its use in the treatment of waters, using either the mucilage or the whole cladode powder. The use of these products in the treatment of municipal or even industrial wastewaters could give rise to diverse benefits. From the environmental point of view, treated waters with neither Fe nor Al, nor synthetic polymers would be obtained (with less toxicity risk). Besides, the produced sludges would be smaller in amount, with better biodegradability, and lower metals content. From the economical point of view, the use of these biopolymers would give an added value to the Opuntia and Prosopis culture in Mexico, helping small communities to enhance their incomes by producing environmental-friendly products. This work shows that both Prosopis galactomannan and Opuntia mucilage can be used to treat municipal wastewaters with an initial organic charge of about 827 mg/L as COD by the coagulation-flocculation process, with COD removals for the mesquite seed gum of up to 90% (pH 10, dose of 75 mg/L) and of 60% (pH 7, doses of 50 and 150 mg/L). In the case of mucilage, 65% of the initial COD was removed at pH 10 (dose of 50 mg/L). These figures are very promising for the treatment of wastewaters, with environmental-friendly products.
文摘Prosopis farcta, a plant belongs to the mimosoideae, is characterized by a very wide spectrum of various bioactive and medical constituents. Vitexin, the marker flavonoid found in Prosopis, has potent and broad antitumour efficacy in preclinical models. Many studies had been done for the isolation of flavonoids (vitexin) by completely different chromatographically methodology. During this study, vitexin was isolated from Prosopis farcta by 6 different extraction methods in which parameters as the type, concentration and pH of the extracting solvents considered. Among different solvent systems used, methanol-water (40%, containing acetic acid 0.5%) was found to be the best solvent generating the highest yield (0.554 mg·g-1 DW) from Prosopis leaves. The present work suggests an efficient method for estimation the greatest content of vitexin analyzed by HPLC technique and introduces Prosopis farcta as a suitable source of this flavonoid with several pharmacological properties.
文摘Drastic changes have occurred in Siti zone rangeland over nearly the last three decades, due to rapid land conversion dynamics in the area. In the zone, the land-use change over time and space and temporal trends rangeland condition have never been studied. This study analyzed land use and land cover (LULC) change dynamics since the 1980s. Three dates, 1985, 2001 and 2017, Landsat images were used for classification and analysis of the various LULC. The three images were geo-referenced, re-sampled and processed for classification, using the maximum likelihood classifier algorithm. Moreover, field observations and information from local people were used for triangulation to patterns LULC dynamics. From 1985 to 2017, the general trend observed in the land use/cover change in the rangeland resources in the study districts implies a loss of grassland cover was compensated by an increase in cultivated areas, settlement and shrub/bush land cover. Moreover, the encroachments of invasive plant, Prosopis, settlement and the promotion of cultivation to pastoral way of livelihood have exacerbated the decline of rangeland cover. The study findings have shown important changes in the LULC patterns in the north-eastern Somali rangelands of eastern Ethiopia. These trends are certainly the characteristics of a pastoral way of life turn to settlement. This suggests that major changes in the socio-ecological driving forces affecting landscape dynamics have occurred in the last three decades or so.
基金supported by the Core Research Grant of SERB–DST,New Delhi,Government of India。
文摘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.
文摘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.
文摘The aim of this research was to investigate the interactions between Prosopis plants and soils in the Kalahari area, south west of Botswana. The underlying assumptions of the research were that Prosopis plants significantly enhanced the nutrient content and improved the condition of soils in the study area, and that the height and canopy size of Prosopis plants affected the interactions between Prosopis plants and the soils. Firstly, soil samples were collected under 42 randomly selected Prosopis plant canopies and in the spaces between Prosopis plant canopies at the depth of 0 -20 cmand 60 –80 cm. Secondly, soil samples were collected under 45 randomly selected Prosopis plant canopies of three different categories of height and canopy size at the depth of 0 -10 cm. The soil samples were analysed for soil organic carbon, pH, total nitrogen (N), electrical conductivity (EC), calcium (Ca), sodium (Na), potassium (K), and magnesium (Mg). Soil collected under Prosopis plant canopies and in the spaces between Prosopis plant canopies showed statistically significant difference in the soil organic carbon content (F = 2.68, P = 0.05, α = 0.05), pH (F = 44.81, P α = 0.05) and electrical conductivity (EC) (F = 3.75, P = 0.01, α = 0.05). Statistically significant difference was also observed in the comparison of soils existing under Classes 1, 2 and 3 Prosopis plant canopies in relation to pH and EC (F = 6.56, P = 0.01 and F = 4.77, P = 0.01 respectively at α = 0.05). Therefore, it was concluded that the fundamental assumptions of the study were valid.
文摘The morphological variability of Prosopis africana in its natural range (which includes three climate zones: Guinean zone, Sudano-Guinean zone and Sudanese zone) of Benin was studied on the basis of forest inventory carried out in three different vegetation types (savannah, fallow and field). The data recorded in 139 plots of 1000 m2 each related to the diameter at breast height (1.3 m over the ground level), the bole height, the height to the first branch, crown height, the crown diameter, number of branches on each individual tree. In these plots, 143 sheets were used to determine the length of leaf, the pinna length, leaflets’ length, numbers of pinna, the number of leaflets, and the stalk diameter. In addition, 735 cloves were measured to determine the fruit pods’ diameter, pod length, the total fruit weight and number of seeds per fruit, the seed length, the weight of a seed, and pulp weight. Analysis of variance components shows that the variability of Prosopis is generally greater among individuals than within vegetation types and climatic zones. Discriminant analysis showed that of the 19 morphometric characters seven (7) in the vegetation types and twelve (12) in climate zones revealed a statistically significant discriminating pattern r (prob. P. africana trees measured, 10 morphogroups were depicted on the basis of 19 morphometric characteristics (R2 = 52.6%).
文摘An experiment was initiated in 2008 to evaluate the impact of irrigation regimes on germination and growth patterns of seedlings of Prosopis cineraria in the arid areas of Thar, India. Seeds collected from dried pods of P cineraria were sown in polybags placed in nursery beds. Different irrigation regimes were provided to different beds and data regarding germination and growth were recorded to study natural regeneration. The study revealed that irrigation regimes significantly affected the germination and growth of P cineraria under nursery conditions. The germination rate declined as the irrigation regime shifted from a daily to a fortnightly ba- sis. Height of the seedlings also declined with a decrease in the intensity of irrigation. Thus, it can be concluded that germination and growth of seedlings of P cineraria under nursery conditions can be enhanced by providing irrigation at regular intervals.
文摘Arbuscular mycorrhizal （AM） fungi associated with Prosopis cineraria （Khejri） were assessed for their qualitative and quantitative distribution from eight districts of Rajasthan. A total of three species of Acaulospora, one species of Entrophospora, two species of Gigaspora, twenty-one species of Glomus, seven species of Sclerocystis and three species of Scutellospora were recorded. A high diversity of AM fungi was observed and it varied at different study sites. Among these six genera, Glomus occurred most frequently. Glomus fasciculatum, Glomus aggregatum, and Glomus mosseae were found to be the most predominant AM fungi in infecting Prosopis cineraria. Acaulospora, G. fasciculatum, Sclerocystis was found in all the fields studied, while Scutellospora species were found only in few sites. A maximum of thirty-six AM fungal species were isolated and identified from Jodhpur, whereas only thirteen species were found from Jaisalmer. Spores of Glomusfasciculatum were found to be most abundant under Prosopis cineraria.
文摘This study investigated the antifungal activity of leaf extracts of Prosopis africana and Anacardium occidentale against Macrophomina phaseolina, the causal agent of root rot of Sesamum indicum L. Phytochemical analysis of the two plants showed the presence of alkaloids, saponins, tannins, flavonoids and anthraquinones in petroleum ether, ethyl acetate, methanol and water extracts. The effectiveness of the two medicinal plants viz: P. africana and A. occidentale was tested against the causative agent of root rot of Sesamum indicum L. The effect of plant leaf extracts on mycelia growth of the test organism shows that both P. africana and A. anacardium reduced the mycelia growth significantly as compared to the control (plate, 2, 3, 4). The antifungal property of P. africana and A. occidentale makes these plants of potential interest for the control of the fungi Macrophomina phaseolina.
文摘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.
基金funded by the National University of Río Negro, Argentina (PI40c658, PI40c654)。
文摘Degradation processes affect a vast area of arid and semi-arid lands around the world and damage the environment and people′s health. Degradation processes are driven by human productive activities that cause direct and indirect effects on natural resources, such as species extinction at regional scale, reduction and elimination of vegetation cover, soil erosion, etc. In this context, ecological rehabilitation is an important tool to recover key aspects of the degraded ecosystem. Rehabilitation trials rely on the use of native plant species with characteristics that allow them to obtain high survival and growth rates. The aim of this work was to assess the survival and growth of native woody species in degraded areas of northeastern Patagonia and relate them to plant functional traits and environmental variables. We observed high early and late survival rates, and growth rates in Prosopis flexuosa DC. var. depressa F.A. Roig and Schinus johnstonii F.A. Barkley, and low values in Condalia microphylla Cav. and Geoffroea decorticans(Gillies ex Hook. & Arn.) Burkart. Early survival rates were positively associated with specific leaf area(SLA) and precipitation, but negatively associated with wood density, the maximum mean temperature of the warmest month and the minimum mean temperature of the coldest month. Late survival rates were positively associated with SLA and soil organic matter, but negatively associated with plant height and precipitation. The temperature had a positive effect on late survival rates once the plants overcame the critical period of the first summer after they were transplanted to the field. Prosopis flexuosa and S. johnstonii were the most successful species in our study. This could be due to their functional traits that allow these species to acclimatize to the local environment. Further research should focus on C. microphylla and G. decorticans to determine how they relate to productive conditions, acclimation to environmental stress, auto-ecology and potential use in ecological rehabilit
基金This work was financed by a Foundation for Research on Nature Conservation(S072.65)grant to S.S.M.a Dutch NWO Meervoud(836.05.021)grant to M.H.a NWO ALW-Vici(865.05.002)grant to W.H.v.d.P.
文摘Plants are able to influence their growing environment by changing biotic and abiotic soil conditions.These soil conditions in turn can influence plant growth conditions,which is called plant–soil feedback.Plant–soil feedback is known to be operative in a wide variety of ecosystems ranging from temperate grasslands to tropical rain forests.However,little is known about how it operates in arid environments.We examined the role of plant–soil feedbacks on tree seedling growth in relation to water availability as occurring in arid ecosystems along the west coast of South America.Methods In a two-phased greenhouse experiment,we compared plant–soil feedback effects under three water levels(no water,10%gravimetric moisture and 15%gravimetric moisture).We used sterilized soil inoculated with soil collected from northwest Peru(Prosopis pallida forests)and from two sites in north-central Chile(Prosopis chilensis forest and scrublands without P.chilensis).Important Findings Plant–soil feedbacks differed between plant species and soil origins,but water availability did not influence the feedback effects.Plant–soil feedbacks differed in direction and strength in the three soil origins studied.Plant–soil feedbacks of plants grown in Peruvian forest soil were negative for leaf biomass and positive for root length.In contrast,feedbacks were neutral for plants growing in Chilean scrubland soil and positive for leaf biomass for those growing in Chilean forest soil.Our results show that under arid conditions,effects of plant–soil feedback depend upon context.Moreover,the results suggest that plant–soil feedback can influence trade-offs between root growth and leaf biomass investment and as such that feedback interactions between plants and soil biota can make plants either more tolerant or vulnerable to droughts.Based on dissecting plant–soil feedbacks into aboveground and belowground tissue responses,we conclude that plant–soil feedback can enhance plant colonization in some arid ecosystems by promoting root
