Protist and Plant Growth-Promoting Bacterium Interaction Alters GH3-2 Expression and Enhances Nutrient Content in Rice

The present study aimed to assess the interactive effects of four plant growth-promoting bacterium(PGPB)species[Providencia sp.(Pr),Stenotrophomonas sp.(St),Morganella sp.(Mo),and Lysinibacillus sp.(Lb)]and six protist species[two amoebae Vermamoeba vermiformis(A9)and Acanthamoeba genotype T4(A34),and four ciliates Crytolophosis mucicola(C1),Tetrahymena sp.(C2),Colpoda elliotti(C12),and an unidentified genus of the family Kreyellidae(C5)]on the uptake of nutrients and the expression of auxin-responsive gene(GH3-2)in rice.The findings revealed that rice seedlings grew healthily,and a statistically significant difference was observed after 30 d of incubation in pots under greenhouse conditions treated with each PGPB and protist-PGPB consortia,compared with the untreated control plants.However,the protist-PGPB treatments were more significant than PGPB treatment alone.The greatest improvement in rice seedling growth was observed in C.elliotti with Stenotrophomonas sp.(C12St)treatment,showing increased root and shoot length(88.57%and 79.69%).

Plant growth-promoting properties and anti-fungal activity of endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta in arid lands

Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathogenic fungal mycelia.In this study,an experiment was conducted in August 2022 to explore the growth-promoting potential of endophytic bacterial strains isolated from two medical plant species,Thymus altaicus and Salvia deserta,using a series of screening media.Plant samples of Thymus altaicus and Salvia deserta were collected from Zhaosu County and Habahe County in Xinjiang Uygur Autonomous Region,China,in July 2021.Additionally,the inhibitory effects of endophytic bacterial strains on the four pathogenic fungi(Fusarium oxysporum,Fulvia fulva,Alternaria solani,and Valsa mali)were determined through the plate confrontation method.A total of 80 endophytic bacterial strains were isolated from Thymus altaicus,while a total of 60 endophytic bacterial strains were isolated from Salvia deserta.The endophytic bacterial strains from both Thymus altaicus and Salvia deserta exhibited plant growth-promoting properties.Specifically,the strains of Bacillus sp.TR002,Bacillus sp.TR005,Microbacterium sp.TSB5,and Rhodococcus sp.TR013 demonstrated strong cellulase-producing activity,siderophore-producing activity,phosphate solubilization activity,and nitrogen-fixing activity,respectively.Out of 140 endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta,104 strains displayed anti-fungal activity against Fulvia fulva,Alternaria solani,Fusarium oxysporum,and Valsa mali.Furthermore,the strains of Bacillus sp.TR005,Bacillus sp.TS003,and Bacillus sp.TSB7 exhibited robust inhibition rates against all the four pathogenic fungi.In conclusion,the endophytic bacterial strains from Thymus altaicus and Salvia deserta possess both plant growth-promoting and anti-fungal properties,making them promising candidates for future development as growth-promoting agents and biocontrol tools for plant diseases.

Combining ectomycorrhizal fungi and plant growth-promoting rhizobacteria to enhance salt tolerance of Metasequoia glyptostroboides

Plant growth and productivity are negatively affected by soil salinity.This study investigated the effects of the rhizosphere-promoting bacterium,Bacillus paramycoides JYZ-SD5,and the ectomycorrhizal fungus,Schizophyllum commune Be,on the growth of Metasequoia glyptostroboides under salt stress.Changes in biomass,root growth,root ion distribution and in vivo enzyme activities were determined under different treatments(Be,JYZ-SD5,and Be+JYZ-SD5).The results show that all inoculations increased chlorophyll content,shoot length and root diameter with or without salt stress,and the effect of Be+JYZ-SD5was the strongest.JYZ-SD5 and Be+JYZ-SD5 treatments significantly increased root length,surface area,bifurcation number,tip number,main root length and diameter under salt stress.Normal chloroplast structures developed under both single and double inoculations.Relative to the control,root activities of M.glyptostroboides in the Be,JYZSD5,and Be+JYZ-SD5 treatments increased by 31.3%,17.2%,and 33.7%.All treatments increased the activities of superoxide dismutase(SOD),peroxidase(POD),Na^(+)-K^(+)-ATPase and Ca^(2+)-Mg^(2+)-ATPase.The strongest effect was by Be+JYZ-SD5.Analysis of root ion distribution showed that,under salt stress,Na^(+)and K^(+)decreased and were concentrated in the epidermis or cortex.Na/K ratios also decreased.The Be+JYZ-SD5 treatment increased betaine by 130.3%and 97.9%under 50 mM and 100 mM salt stress,respectively.Together,these changes result in the activation of physiological and biochemical processes involved in the mitigation of salinity-induced stress in M.glyptostroboides.

Plant growth-promoting rhizobacteria(PGPR)and its mechanisms against plant diseases for sustainable agriculture and better productivity

Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with the plants.These bacteria viz.,Agrobacterium,Arthobacter,Azospirillum,Bacillus,Burkholderia,Flavobacterium,Pseudomonas,Rhizobium,etc.,play important role in plant growth promotion.In addition,such symbiotic associations of PGPRs in the rhizospheric region also confer protection against several diseases caused by bacterial,fungal and viral pathogens.The biocontrol mechanism utilized by PGPR includes direct and indirect mechanisms direct PGPR mechanisms include the production of antibiotic,siderophore,and hydrolytic enzymes,competition for space and nutrients,and quorum sensing whereas,indirect mechanisms include rhizomicrobiome regulation via.secretion of root exudates,phytostimulation through the release of phytohormones viz.,auxin,cytokinin,gibberellic acid,1-aminocyclopropane-1-carboxylate and induction of systemic resistance through expression of antioxidant defense enzymes viz.,phenylalanine ammonia lyase(PAL),peroxidase(PO),polyphenyloxidases(PPO),superoxide dismutase(SOD),chitinase andβ-glucanases.For the suppression of plant diseases potent bio inoculants can be developed by modulating the rhizomicrobiome through rhizospheric engineering.In addition,understandings of different strategies to improve PGPR strains,their competence,colonization efficiency,persistence and its future implications should also be taken into consideration.

Potential seed germination-enhancing plant growth-promoting rhizobacteria for restoration of Pinus chiapensis ecosystems

Rhizosphere soil samples of three Pinus chiapensis sites were analyzed for their physicochemical properties,soil bacteria isolated and screened in vitro for growthpromoting abilities.Nine isolates that showed promise were identified to five genera Dyella,Luteimonas,Euterobacter,Paraburkholderia and Bacillus based on the sequences of16 S rRNA gene.All the strains were isolated from nondisturbed stands.These bacteria significantly decreased germination time and increased sprout sizes.Indole acetic acid and gibberellin production and phosphate solubilisation were detected.Results indicate that these biochemicals could be essential for P.chiapensis distribution and suggest the possibility that PGPR inoculation on P.chiapensis seeds prior to planting could improve germination and possibly seedling development.

Synergistic combination of arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria modulates morpho-physiological characteristics and soil structure in Nitraria tangutorum bobr.Under saline soil conditions

Nitraria tangutorum Bobr.,a typical xero-halophyte,can be used for vegetation restoration and reconstruction in arid and semiarid regions affected by salinity.However,global climate change and unreasonable human activity have exacerbated salinization in arid and semi-arid regions,which in turn has led to the growth inhibition of halophytes,including N.tangutorum.Arbuscular mycorrhizal fungi(AMF)and plant growth-promoting rhizobacteria(PGPR)have the potential to improve the salt tolerance of plants and their adaptation to saline soil environments.In this study,the effects of single and combined inoculations of AMF(Glomus mosseae)and PGPR(Bacillus amyloliquefaciens FZB42)on N.tangutorum were evaluated in severe saline soil conditions.The results indicate that AMF and PGPR alone may not adapt well to the real soil environment,and cannot ensure the effect of either growth promotion or salt-tolerance induction on N.tangutorum seedlings.However,the combination of AMF and PGPR significantly promoted mycorrhizal colonization,increased biomass accumulation,improved morphological development,enhanced photosynthetic performance,stomatal adjustment ability,and the exchange of water and gas.Co-inoculation also significantly counteracted the adverse effect of salinity on the soil structure of N.tangutorum seedlings.It is concluded that the effectiveness of microbial inoculation on the salt tolerance of N.tangutorum seedlings depends on the functional compatibility between plants and microorganisms as well as the specific combinations of AMF and PGPR.

Application Progress of Plant Growth-promoting Bacteria in Crops

Plant growth-promoting bacteria(PGPBs)can promote plant growth and improve crop yield.They can induce plant systemic resistance to resist biotic and abiotic stresses.In recent years,with the development of green ecological agriculture,new biological fertilizers such as microbial inocula and microbial fertilizers based on PGPBs have been gradually applied in crop planting.Based on plant growth promotion and disease control,the application progress of PGPBs in crops from the aspects of growth promotion mechanism,growth promotion effect,resistance to biological and abiotic stresses were discussed,aiming to provide reference for the relevant research and application of PGPBs in crops.

Effect of Plant Growth-Promoting Rhizobacteria at Various Nitrogen Rates on Corn Growth

Plant growth-promoting rhizobacteria (PGPR) colonize plant roots and promote plant growth by producing and secreting various chemical regulators in the rhizosphere. With the recent interest in sustainable agriculture, an increasing number of researchers are investigating ways to improve the efficiency of PGPR use to reduce chemical fertilizer inputs needed for crop production. Accordingly, greenhouse studies were conducted to evaluate the impact of PGPR inoculants on biomass production and nitrogen (N) content of corn (Zea mays L.) under different N levels. Treatments included three PGPR inoculants (two mixtures of PGPR strains and one control without PGPR) and five N application levels (0%, 25%, 50%, 75%, and 100% of the recommended N rate of 135 kg N ha−1). Results showed that inoculation of PGPR significantly increased plant height, stem diameter, leaf area, and root morphology of corn compared to no PGPR application under the same N levels at the V6 growth stage, but few differences were observed at the V4 stage. PGPR with 50% of the full N rate produced corn biomass and N concentrations equivalent to or greater than that of the full N rate without inoculants at the VT stage. In conclusion, mixtures of PGPR can potentially reduce inorganic N fertilization without affecting corn plant growth parameters. Future research is needed under field conditions to determine if these PGPR inoculants can be integrated as a bio-fertilizer in crop production nutrient management strategies.

Plant growth-promoting characteristics of root fungal endophytes isolated from a traditional Cordillera rice landrace

This study was conducted to isolate and characterize the plant growth-promoting potential of fungal endophytes from the roots of Diket red,a traditional rice plant from the Cordillera,Northern Luzon.Eighteen morphospecies of filamentous endophytes were isolated of which twelve isolates were successfully identified to the species level.These isolates were identified as Aspergillus versicolor,Aspergillus sp.,Chaetosphaeria sp.,Cladosporium cladosporioides,Hypocrea lixii,Microascus murinus,and Trichoderma harzianum.The identified twelve isolates were selected to screen in vitro for their plant growth-promoting characteristics,and evaluated in vivo for their beneficial effects on seedling vigor and early seedling growth.Isolate PPL14 produced the highest IAA at 55.5μg ml^(-1)and M.murinus PPL10 produced the highest amount of IAA at 3.73μg IAA mg^(-1)dry mycelia wt.The seedling vigor assay and in vivo plant growth promotion bioassay indicated overall positive effects of culture filtrate(CF)application of the endophyte isolates.Rice seeds and seedlings grown in aseptic condition and treated with endophyte CFs displayed significantly enhanced levels of germination,seedling vigor,shoot,root,and total plant growth,and biomass compared to non-treated control.Other plant growth-promoting characteristics were also studied including phosphate solubilization,siderophore production,ammonia production,and catalase activity.This study supports the potential use of fungal endophytes as bio-inoculants for plant growth promotion and enhancement of nutrient assimilation of agriculturally important crops.

Research Progress on the Growth-Promoting Effect of Plant Biostimulants on Crops

A Plant Biostimulant is any substance or microorganism applied to plants to enhance nutrition efficiency,abioticstress tolerance,and/or crop quality traits,regardless of its nutrient content.The application of Plant biostimulants(PBs)in production can reduce the application of traditional pesticides and chemical fertilizers and improvethe quality and yield of crops,which is conducive to the sustainable development of agriculture.An in-depthunderstanding of the mechanism and effect of various PBs is very important for how to apply PBs reasonablyand effectively in the practice of crop production.This paper summarizes the main classification of PBs;Thegrowth promotion mechanism of PBs was analyzed from four aspects:improving soil physical and chemical properties,enhancing crop nutrient absorption capacity,photosynthesis capacity,and abiotic stress tolerance;At thesame time,the effects of PBs application on seed germination,seedling vigor,crop yield,and quality were summarized;Finally,how to continue to explore and study the use and mechanism of PBs in the future is analyzedand prospected,to better guide the application of PBs in crop production in the future.

Rice(Oryza sativa L.)plant protection using dual biological control and plant growth-promoting agents:Current scenarios and future prospects

Various microorganisms live in association with different parts of plants and can be harmful,neutral,or beneficial to plant health.Some microbial inhabitants of plants can control plant diseases by contesting with,predating on,or antagonizing plant pathogens and by inducing systems for plant defense.A range of methods,including plant growth-promoting microorganisms(PGPMs)as biological control agents(BCAs)(BCA-PGPMs)are used for the biological management and control of plant pathogens.Some BCAs interact with plants by inducing resistance or priming plants without direct interaction with the pathogen.Other BCAs operate via nutrient competition or other mechanisms to modulate the growth conditions for the pathogen.Generally,PGPMs can be applied alone or together with other chemicals or carriers to control various crop diseases.This review highlights the effective types of BCA-PGPMs and their applications,roles,carrier based-formulations,and responses to rice(Oryza sativa L.)pathogens.Future plant disease management prospects are promising,and growers’increasing demand for BCA-PGPM products can be exploited as an effective approach to the management of plant diseases,as well as to improve yield,environmental protection,biological resources,and agricultural system sustainability.

Effect of arsenic on tolerance mechanisms of two plant growth-promoting bacteria used as biological inoculants

Bacterial ability to colonize the rhizosphere of plants in arsenic（As） contaminated soils is highly important for symbiotic and free-living plant growth-promoting rhizobacteria（PGPR）used as inoculants, since they can contribute to enhance plant As tolerance and limit metalloid uptake by plants. The aim of this work was to study the effect of As on growth,exopolysaccharide（EPS） production, biofilm formation and motility of two strains used as soybean inoculants, Bradyrhizobium japonicum E109 and Azospirillum brasilense Az39. The metabolism of arsenate（As（V）） and arsenite（As（III）） and their removal and/or possible accumulation were also evaluated. The behavior of both bacteria under As treatment was compared and discussed in relation to their potential for colonizing plant rhizosphere with high content of the metalloid. B. japonicum E109 growth was reduced with As（III）concentration from 10 μM while A. brasilense Az39 showed a reduction of growth with As（III） from 500 μM. EPS and biofilm production increased significantly under 25 μM As（III）for both strains. Moreover, this was more notorious for Azospirillum under 500 μM As（III）,where motility was seriously affected. Both bacterial strains showed a similar ability to reduce As（V）. However, Azospirillum was able to oxidize more As（III）（around 53%） than Bradyrhizobium（17%）. In addition, both strains accumulated As in cell biomass. The behavior of Azospirillum under As treatments suggests that this strain would be able to colonize efficiently As contaminated soils. In this way, inoculation with A. brasilense Az39 would positively contribute to promoting growth of different plant species under As treatment.

基于Plant Simulation的化纤自动落丝系统仿真实验分析

基于Plant Simulation软件,构建一种化纤自动落丝系统的3D数字化模型,对系统效率关键输入因子进行参数化设置,将系统各工位三维数字模型导入软件中建立层次化运动机构图形结构,并运用Simltalk语言实现三维动作仿真,通过基础物理参数设置,保证了仿真数字化模型与现实系统更具一致性。通过多级实验设计分析了系统影响因子对于系统效率的影响特性曲线,并进一步通过动态参数化实验方法,计算出双输入因子对系统效能影响的敏感度。该实验结果可为化纤自动落丝系统的建设成本控制与可行性分析提供指导,具有较好的工程应用价值。

基于Plant Simulation的压气机叶片型线加工产线分析与优化

运用专业仿真软件Plant Simulation,根据压气机叶片型线机械加工工艺特点和物料运行流程建立生产线仿真模型,从产能、设备利用率及产线瓶颈等多方面进行仿真分析与优化。结果表明:Plant Simulation仿真平台的仿真可以找出规划设计方案中存在的问题并验证方案的合理性。该仿真结果为型线机械加工产线的优化设计提供了可靠依据,达到了节约投资成本和缩短设计周期的目的。

Effects of Plant Growth-Promoting Rhizobacteria and N Source on Plant Growth and N and P Uptake by Tomato Grown on Calcareous Soils

Introducing specific microorganisms into the soil ecological system is an important strategy for improving nutrient use efficiency.Two pot experiments were conducted in the greenhouse from December 3, 2012 to January 25, 2013(Experiment 1) and March 11 to April 23, 2013(Experiment 2) to evaluate the effect of nitrogen(N) source and inoculation with plant growth-promoting rhizobacteria(PGPR) on plant growth and N and phosphorus(P) uptake in tomato(Lycopersicon esculentum Mill.) grown on calcareous soils from South Florida, USA.Treatments included urea, controlled release urea(a controlled release fertilizer, CRF) each at low and high N rates and with or without inoculation of PGPR.A mixture of PGPR strains Bacillus amyloliquefaciens IN937 a and Bacillus pumilus T4 was applied to the soil during growing periods of tomato.Treatments with PGPR inoculation increased plant height compared to treatments without PGPR in both experiments.Inoculation with PGPR increased shoot dry weight and shoot N uptake for the same N rate and N source.In both experiments, only at high N rate, CRF and urea treatments with PGPR had significantly(P < 0.05)greater shoot biomass than those without PGPR.Only at high N rate, CRF treatment with PGPR significantly increased shoot N uptake by 39.0% and 10.3% compared to that without PGPR in Experiments 1 and 2, respectively.Meanwhile, presence of PGPR in the soil increased shoot P uptake for all treatments in Experiment 1 and for most treatments in Experiment 2.In Experiment 1, only at low N rate, CRF treatment with PGPR significantly increased shoot P uptake compared with that without PGPR.In Experiment2, a significant increase in shoot P uptake by inoculation of PGPR was only observed in CRF treatment at high N rate.Results from this study indicate that inoculation with PGPR may increase plant growth and N and P uptake by tomato grown on calcareous soils.However, the effect of PGPR varied and was influenced by many factors such as N source, N rate, and soil fertility.Further investigations are warranted to confirm the effect of PGPR under different soil conditions.

Halophile plant growth-promoting rhizobacteria induce salt tolerance traits in wheat seedlings(Triticum aestivum L.)

Salinity is one of the most important growth-limiting factors for most crops in arid and semi-arid regions;however,the use of plant growth-promoting rhizobacteria isolated from saline soils could reduce the effects of saline stress in crops.This study aimed to evaluate the efficiency of plant growth-promoting rhizobacteria(PGPRs),isolated from the rhizosphere of halophile plants,for the growth,Na^+/K^+balance,ethylene emission,and gene expression of wheat seedlings{Triticum aestivum L.)grown under saline conditions(100 mmol L^-1 NaCl)for 14 d.A total of 118 isolates obtained from saline soils of the deserts of Iran were tested for their capacity as PGPRs.Out of the 118 isolates,17 could solubilize phosphate(Ca3(P〇4)2),5 could produce siderophores,and 16 could synthesize indole-3-acetic acid.Additionally,PGPRs were also evaluated for aminocyclopropane-l-carboxylate deaminase activity.A pot experiment was conducted to evaluate the ability of 28 PGPR isolates to promote growth,regulate Na^+/K^+balance,and decrease ethylene emissions in plants.The most efficient PGPRs were Arthrobacter aurescens.Bacillus atrophaeus,Enterobacter ashuriae,and Pseudomonas fluorescens.Gene expression analysis revealed the up-regulation of H^+-PPase,HKT1,NHX7,CAT,and APX expression in roots of Enterobacter-inocuVdied salt-stressed plants.Salt-tolerant rhizobacteria exhibiting plant growth-promoting traits can facilitate the growth of wheat plants under saline conditions.Our results indicate that the isolation of these bacteria may be useful for formulating new inoculants to improve wheat cropping systems in saline soils.

Autochthonous halotolerant plant growth-promoting rhizobacteria promote bacoside A yield of Bacopa monnieri(L.)Nash and phytoextraction of salt-affected soil

Phytoremediation is a promising approach for reclamation of salt-affected soil.Phytoextraction is the most commonly used process,which exploits plants to absorb,immobilize,and accumulate salt in their shoots.In this study,halotolerant plant growth-promoting rhizobacteria(PGPR)were isolated from the rhizosphere of wild grasses growing naturally in salt-affected areas of Lucknow,Uttar Pradesh(India)and were tested for their efficacies of salt-tolerance and plant growth-promoting(PGP)abilities.Based on 16S rRNA sequences,the most efficient halotolerant isolates possessing PGP traits were identified as Pseudomonas plecoglossicida(KM 233646),Acinetobacter calcoaceticus(KM 233647),Bacillus flexus(KM 233648),and Bacillus safensis(KM 233652).Application of these isolates as bio-inoculants significantly(P<0.05)increased the growth and bacoside A yield of a medicinal plant,Bacopa monnieri(L.)Nash,grown on natural salt-affected soil.The phytoremediation of salt-affected soil was evident by the substantial increase in shoot Na^+:K^+ratio of bio-inoculant-treated plants.When compared to un-inoculated control plants,the soil physico-chemical properties of bio-inoculant-treated plants were improved.The shoot and root biomass(fresh and dry weights),soil enzymes,and soil nutrient parameters showed significant positive correlations with the shoot Na+:K+ratio.Consequently,the halotolerant PGPR screened in this study could be useful for the reclamation of saline soils concomitant with improved plant growth and bacoside A yield.

Grain yield and N uptake of maize in response to increased plant density under reduced water and nitrogen supply conditions

The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.However,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains unknown.This study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to 2021.The treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N supply.When water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme activities.Compared with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improved urease activity and nitrate reductase activity by 5.4% at the R2(blister)stage and 19.6% at the V6(6th leaf)stage,and increased net income and the benefit:cost ratio by 22.1 and 16.7%,respectively.W1N1D2 and W1N2D2 reduced the nitrate nitrogen and ammoniacal nitrogen contents at the R6 stage in the 40-100 cm soil layer,compared with W2N2D1.In summary,increasing the planting density by 30% can compensate for the loss of grain yield and aboveground N accumulation under reduced water and N inputs.Meanwhile,increasing the maize density by 30% improved grain yield and aboveground N accumulation when water was reduced by 20% while the N application rate remained constant in arid irrigation areas.

Influence of Topography on the Distribution and Structure of Woody Plants in the Senegalese Sahel (Sandy Ferlo)

This study describes the floristic composition and structure of a woody stand in the Senegalese Sahel, paying particular attention to the edaphic factors of its floristic composition. A stratified inventory considering the different relief units was adopted. Woody vegetation was surveyed using a dendrometric approach. The results obtained show that the flora is dominated by a few species adapted to drought, such as Balanites aegyptiaca (L.) Del., Calotropis procera Ait. and Boscia senegalensis (Pers.). The distribution of this flora and the structure of the ligneous plants are linked to the topography. In the lowlands, the flora is more diversified and the ligneous plants reach their optimum level of development compared with the higher relief areas. In the lowlands, there are a few woody species which, in the past, were indicative of better climatic conditions. These are Anogeissus leiocarpus (DC.), Commiphora africana (A. Rich.), Feretia apodanthera Del., Loeseneriella africana (A. Smith), Mitragyna inermis (Willd.) and Sclerocarya birrea (A. Rich). It is important that their reintroduction into reforestation projects takes account of their edaphic preference.

SPATULA as a Versatile Tool in Plant:The Progress and Perspectives of SPATULA(SPT)Transcriptional Factor

With the rapid development of modern molecular biology and bioinformatics,many studies have proved that transcription factors play an important role in regulating the growth and development of plants.SPATULA(SPT)belongs to the bHLH transcription family and participates in many processes of regulating plant growth and development.This review systemically summarizes the multiple roles of SPT in plant growth,development,and stress response,including seed germination,flowering,leaf size,carpel development,and root elongation,which is helpful for us to better understand the functions of SPT.