The Effect of iron fertilization on nodulation, yield and yield traits of soybean genotypes with different maturity groups as affected by Brady Rhizobium Inoculations

Iron (Fe) deficiency is the major constraint for soybean cultivation in calcareous soils. Its availability affects symbiotic association of the host plant and the endosymbiont and eventually the yield of soybean. However, the effectiveness of integrated application of Bradyrhizobium and Fe fertilizer on nodulation and yield of soybean genotypes with different maturity group has not been studied. Therefore, the objective of this study was to evaluate the effect of Bradyrhizobium inoculated soybean genotypes with different maturity group on FeSO4 and Fe-EDTA nutrient requirement supplied through the foliage and applied directly to the soil. The experiment was conducted under greenhouse and field conditions. Six soybean genotypes, three late maturing (Wogayen, TGx-1336424 and Belsa) and the remaining three medium maturing (GIZA, Afgat and Gishame) were used for greenhouse experiment. Based on the greenhouse result, only two promising genotypes, namely GIZA and TGx-1336424, were selected for further investigation under field experiment. Eight treatments which synthesized by combining three Bradyrhizobium inoculations, with and without Fe fertilizer (0 and 4 mg kg-1 soil), including N-treated (20 kg N ha-1) and the control, were tested in pot experiment arranged in a completely randomized design (CRD). Four levels of inoculation factorially combined with three levels of Fe-EDTA application were used for field experiment. These treatments were laid out in a spilt plot in randomized complete block design (RCBD) with three replications. The results of the present study indicate significant improvement of most investigated traits of tested medium maturing genotypes, but not for late maturing soybean genotypes under greenhouse conditions. A significant increase of nodule number (NN) and nodule dry weight (NDW) with increasing rates of Fe for selected genotypes were observed in field experiment. Application of Fe, however, showed differential effect on both genotypes on other investigated traits. All investigated traits, except NN, NDW and shoot dry matter (SDW) did not improve significantly by Fe application for TGx-1336424 genotype. In contrast, significant improvement of number of pods per plant (NPP), total biomass yield (TBY), grain yield (GY) and plant total nitrogen concentration (PTC) with increasing rates of Fe were observed for GIZA genotype. The regression analysis indicates different degree of dependence of TBY, NDW, NN and GY of both genotypes with increasing rates of Fe application with different Bradyrhizobium sp. inoculation treatments. Hence, it can be concluded that the effect of Fe application is dependent on maturity groups of soybean genotypes and effectiveness of inoculated Bradyrhizobium sp

Étude de l'effet de la surcharge compensatoire du plantaire sur la dynamique de la transmission synaptique, in situ

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Le rôle des récepteurs aux cannabinoïdes CB1 et CB2 dans le guidage axonal

Au cours du développement, les axones des cellules ganglionnaires de la rétine (CGRs) voyagent sur de longues distances pour établir des connexions avec leurs cellules cibles. La navigation des cônes de croissance est guidée par différentes molécules chimiotropiques présentes dans leur environnement. Les endocannabinoïdes (eCB) sont d’importants neuromodulateurs qui régulent de manière rétrograde la fonction de nombreuses synapses du cerveau. Ils agissent principalement par le biais de leurs récepteurs liés à une protéine Gi/o CB1 (CB1R) et CB2 (CB2R). La présence des eCBs durant le stade fœtal et la période postnatale suggère leur implication dans des événements régulant le développement du système nerveux. Cette thèse confirme l’expression des récepteurs aux cannabinoïdes CB1 et CB2 ainsi que l’enzyme dégradant les eCBs lors du développement embryonnaire et perinatal des CGRs et de la voie rétinothalamique in vivo. La manipulation pharmacologique de l’activité de CB1R et CB2R réorganise la morphologie du cône de croissance des CGRs et des neurones corticaux in vitro. De plus, la stimulation locale avec un agoniste de CB1R ou de CB2R modifie le comportement du cône de croissance entraînant sa répulsion. CB1R et CB2R modulent par le biais de la voie de signalisation AMPc/PKA, la mobilisation de DCC à la membrane plasmique. Par ailleurs, les résultats de cette recherche démontrent également l’implication de CB1R et CB2R dans la ségrégation des projections ipsi- et controlatérales et le développement de la voie rétinothalamique.Following differentiation, retinal ganglion cell (RGC) axons, tipped at their distal end by the growth cone (GC), navigate through relatively long distances in a highly directed manner in order to establish functional synapses with thalamic and superior colliculus (SC) neurons. This is achieved with the help of extracellular guidance molecules which steer RGC axon growth by regulating GC morphology by means of attractive and/or repulsive mechanisms. In the adult brain, endocannabinoids (eCBs) exert an important neuromodulatory function by acting as retrograde messengers to regulate the function of many synapses. Endocannabinoids act mainly via their Gi/o protein coupled receptors CB1 (CB1R) and CB2 (CB2R). Due to their presence at the fetal and early postnatal periods, it has been proposed that eCBs and their receptors might be involved in several developmental events, such as cell proliferation and migration, axon guidance and synaptogenesis. We observed that during early postnatal development, components of the eCB system are expressed along the visual pathway (the optic chiasm, the lateral geniculate nucleus and the SC). To assess the implication of the eCB system, in vitro, embryonic retinal explant and primary neuron cultures were treated with pharmacological agonists and inverse agonists of CB1R and CB2R. These experiments demonstrated that these cannabinoid receptors modify the GC’s morphology. Most importantly, CB1R and CB2R act through the cAMP/PKA pathway to modulate the presence of DCC at the plasma membrane. In vivo, CB1R and CB2R play a major role and the absence of either one of them induces a decrease in eye-specific segregation of retinal projections. These results show an implication of CB1R and CB2R during RGC growth and retinothalamic development

Effect of Inoculating Bradyrhizobium on Phosphorus Use Efficiency and Nutrient Uptake of Soybean in Calcareous Soil, Central Rift Valley, Ethiopia

አህፅሮትከ7.0 ፒ.ኤች በሊይ የአፈር ፎስፈረስ ግዑዝ ስሇማይሟማ በከፍተኛ ሁኔታ ሇዝግጠት ተጋሊጭ ስሇሚሆን ዕፅዋቶች በቀሊለ አያገኙትም፡፡ ስሇዚህ ይህ የምርምር ጥናት በመተሏራ ስኳር ፋብሪካ በ 2008 ዓ.ም ምርት ዗መን የብረዲራይዞቢዬም ባክቴሪያ ክትባት አስተዋፅዖ አኩሪ አተርን ከሸንኮራ አገዳ ጋር በማሰባጠር በፎስፈረስ አወሳሰድና የፎስፈረስ አወሳሰድ ብቃትን ሇመገምገም ዓሊማ አንግቦ በመስኖ ተተግብሯሌ፡፡ ሙከራው ሦስት መጠን የባክቴሪያ ክትባት ማሇትም ላጊዩምፊክስ፣ SB6B1እና ያሌተከተበ እንዲሁም አራት ፎስፈረስ መጠን ማሇትም 0፣ 10፣ 20 እና 30 ኪ.ግ/ሄክታር ፎስፈረስ ወስዯዋሌ፡፡ ሙከራው የተ዗ጋጀው በራንዯማይዝድ ኮምፕሉት ብልክ ዲዛይን በፋክቶሪያሌ የተዯራጀ ሲሆን ሦስት ቅጂ ግሌባጭ አሇው፡፡ የጭብጥ (መረጃ) ትንትና እንዳሚያሰየው ብረዲራይዞቢዬም ክትባት ትርጉም ባሇው ሁኔታ የዕፅዋት ናይትሮጅንና ፎስፈራስ ይ዗ት ሊይ ካሌተከተበ አንፃር አመርቂ ውጤት አሳይቷሌ፡፡ የተሇያዬ የፎስፈረስ መጠን እንዲሁም የፎስፈረስና ክትባት ጥምረት በናይትሮጅንና ፎስፈረስ ይ዗ት ሊይ ትርጉም ያሇው ሌዩነት አሊሳዩም፤ ነገር ግን 30 ኪ.ግ/ሄክታር ፎስፈረስ በጠቅሊሊ ፎስፈረስ ይ዗ት ሊይ ከፍተኛ ሌዩነት አምጥቷሌ፡፡ በብረዲራይዞቢዬም ክትባት ምክንያት ፎስፈረስን የመውሰድ ብቃት ተሻሽሎሌ፡፡ በዚህ መሠረት ከፍተኛ አግሮኖሚክ ኢፊሼንሲ፣ ሪከቨሪ ኢፊሼንሲና ዩትሊይዜሽን ኢፊሼንሲ በSB6B1 ክትባት፤ ፊዚዮልጂካሌ ኢፊሼንሲና አግሮፊዚዮልጂካሌ ኢፊሼንሲ በላጉምፊክስ ክትባት አማካይነት በ10 ኪ.ግ/ሄክታር ፎስፈረስ ሲገኝ አግሮፊዚዮልጂካሌ ኢፊሼንሲ በ30 ኪ.ግ/ሄክታር ፎስፈረስ ተመዝግቧሌ፡፡ በአጠቃሊይ በ10 ኪ.ግ/ሄክታር ፎስፈረስ መጠን SB6B1 ባክቴሪያ ክትባት አመርቂ ውጤት ያስገኘ ሲሆን ላጊዩምፊክስ ዯግሞ ይከተሊሌ፡፡ የፎስፈረስ መውሰድ ብቃትን እንዲጨምር የተሻለ አያያዝ ዗ዴዎችን ማሇትም ፎስፌት የሚያሟሙ ረቂቅ ነፍሳት ወይም ማይኮሪ዗ ብረዲራይዞቢዬም ጋር በማጣመር መጠቀም አስፈሊጊ ነው፡፡ AbstractAt a soil pH value of above 7.0, inorganic phosphorus (P) is highly susceptible to precipitation as insoluble form that is unavailable to plants. Hence, a field experiment was conducted at Metehara Sugar Estate under irrigation during the 2014/15 cropping season to evaluate the effect of inoculating Bradyrhizobium on P uptake and P use efficiency of soybean intercropped with sugarcane. The treatments consisted of three levels of inoculation (Legume fix, SB6B1 and uninoculated) and four rates of P (0, 10, 20 and 30 kg Pha-1). The experiment was laid out in a randomized complete block design (RCBD) in a factorial arrangement and replicated three times. Analysis of the data indicated that Bradyrhizobium inoculation significantly increased plant N concentration and P uptake compared to the uninoculated treatment. The effect of P rates and its interaction with inoculation was not significant on N concentration and P uptake, but significantly increased total P uptake at the application of 30 kg Pha-1. Phosphorus use efficiency indices were improved in response to inoculating the crop with Bradyrhizobium. The highest AE (13.6 kg kg-1), PRE (31.8%) and PUE (10.6 kg kg-1) were obtained by SB6B1 inoculation and the highest PE (117.2 kg kg-1) and APE (161.7 kg kg-1) were obtained by Legumefix inoculation all at 10 kg P ha-1except PE which recorded the highest at 30 kg P ha-1.Thus, it can be concluded that SB6B1 isolate can be used as the best inoculant followed by Legumefix isolate with 10 kg P ha-1of P fertilizer. However, strategies for increasing P use efficiency by adopting best management practices like co-inoculation of phosphate solubilizing microorganism or mycorrhiza with these Bradyrhizobium inoculants should be adopted to enhance P use efficiencies

The Response of Hybrid Maize (Zea mays) to N and P Fertilizers on Nitisols of Yeki District, Sheka Zone

and Environmental Sciences, Haramaya University, Dire Dawa, Ethiopia; 3CIMMYT, Addis Ababa አህፅሮትበኢትዮጵያ ዝቅተኛ የአፈርለምነት በተለይም ናይትሮጅን እና ፎስፎረስ፣ ለሰብል ምርታማነትን ለመጨመር ማነቆ የሆኑ ንጥረ ነገሮች ናቸው፡፡ በዘልማዳዊ ናትሮጂን እናፎስፎረስ ማዳበረያ ምክረሃሳብ ምክኒያት በኢትዮጵያ በብሔራዊ ደረጃ የተዳቀለ የበቆሎ ዝርያ ምርት ዘላቂ እና አጥጋቢ አይደለም፡፡ ስለዚህ የናይተሮጂን እና ፎስፎረስ ማዳበረያን መጠን እና አጠቃቀም በበቆሎ ምርት ላይ አጥጋቢ ምላሽ ለመፈለግ በደቡብ ምዕራብ ኢትዮጵያ የኪ ወረዳበ 2008 ዓ.ም ሁለት የተለያዩ ቦታዎች ላይ የመስክ ሙከራ አድረገን ነበር፡፡ ጥናቱ ሁለት ዓይነት ሙከራዎችን ያካተተ ነበር፤ የመጀመሪያው ጥናት ሰባት የተለያዩ የናይትሮጂን ማዳበሪያ ደረጃዎች ማልትም 0፤ 23፤ 46፤ 69፤ 92፤ 115 እና 138 ኪሎ ግራም በሄክታር ለእያንዳንዳቸው 30 ኪሎ ግራም ፎስፈረስ በሄክታር በመጨመር፤ ሁለተኛው ጥናት ደግሞ ሰባት የተለያዩ የፎስፈረስ ማዳበሪያ ደረጃዎችን ማለትም 0፤ 10፤ 20፤ 30፤ 40፤ 50 እና 60 ኪሎግራም በሄክታር እያንዳንዳቸው 92 ኪሎ ግራም ናይትሮጂን በሄክታር የያዘ ነበር፡፡ እነዚህ የናይትሮጂን እና የፎስፎረስ ደረጃዎች በአራት ረድፎች ውስጥ የተደረደሩ ሲሆን በእያንዳንዱ ረድፍ ሁለም የማዳበሪያ ደረጃዎች የዘፈቀዲዊ አኳኋን እንዱቀመጡተ ደርጓል፡፡ ውጤቶቹ የሚያሳዩት የናይትሮጂን እና የፎስፎረስ ደረጃዎች በበቆሎ ምርት፤ ፎስፎረስ እና ናይትሮጅን ንጠረ ነገሮችን የመጠቀም አቅም እና ዘዴ ላይ ከፍተኛ ተጽዕኖ ያሳደረ መሆኑን ነው፡፡ በአጠቃላይ ፎስፎረስ እና ናይትሮጅን ማዳበሪያ ደረጃዎች በከፍተኛ ፍጥነት ሲጨምሩ ፎስፎረስ እና ናይትሮጅን አጠቃቀም ፍጆታ ይቀንሳል፡፡ ፎስፎረስ እና ናይትሮጅን ማዳበሪዎችን መጨመር በሁለቱም ቦታዎች ላይ ከፍተኛ የሆነ የበቆሎ የጥራጥሬ መጠን፤ የ 1000 ጥራጥሬዎች ክብደት እና ከመሬት በላይ ምርት ጨምሩዋል፡፡ ከፍተኛ የሆነ ምርት ማለትም 8093 ኪሎ ግራም በቆሎ በሄክታር በቴፒእና 8158 ኪሎ ግራም በቆሎ በሄክታር በአዲስ አለም የማምረት አቅምከ 92  እና 69 ኪሎ ገራምና ይትሮጂን ማዳበሪያ በሄክታር በመጨመር በቅደም ተከተል ተገኝቷል፡፡ከፍተኛ ምርት ማለትም 8918 ኪ.ግ በሄክታር በቴፒ እና 8298 ኪ.ግ በሄክታር በአዲስአለም፤ በሁለቱም ቦታዎች 40 ኪ.ግ ፎስፎረስ በሄክታር በመጨመር ማግኘት ተችሉዋል፡፡ በሁለቱም ቦታዎች 69 ኪሎ ግራም ናይትሮጂን በሄክታር፤ እንዲሁም 30 እና 40 ኪሎ ገራም ፎስፎረስ በሄክታር በመጨመር በአዲስአለም እና ቴፒ በቅደም ተከተል በጣም ብዙ ትርፍ ተገኝቷል፡፡ Abstract Low soil fertility, particularly nitrogen(N)and Phosphorus(P) are among the most yield-limiting nutrients in Ethiopia. Due to blanket NP application at the national level, the response of hybrid maize in Ethiopia is inconsistent and not satisfactory. Hence, a field experiment was initiated to investigate the response of hybrid maize (Zea mays L.) to the application of N and P fertilizer rates and their use efficiency on Nitososl. The study comprised two sets of experiments set I had seven levels of N each with30 kg P ha-1(0, 23, 46, 69, 92, 115 and 138 kg N ha-1) while set II had seven levels of phosphorus each with 92 kg N ha-1(0, 10, 20, 30, 40, 50, and 60 kg P ha-1). Both sets of experiments were replicated in two locations. The treatments were laid out separately in a randomized complete block design with four replications. Results showed that N and P rates of application significantly influenced yield and yield components, uptake and nutrient use efficiency. Generally, N and P use efficiency decreased with increased N and P fertilizer rates. Application of NP significantly increased the number of Kernels Cob-1, 1000-kernel weight, and above-ground dry biomass by at both locations. The maximum maize grain yield of 8093 kg ha-1at Tepi and 8158 kg ha-1at Addis Alem were obtained from 92kg N ha-1and 69kg N ha-1, respectively. The maximum grain yields of 8918kg ha-1at Tepi and 8298 kg ha-1at Addis Alem were produced by the application of 40kg Pha-1for both sites. Applications of 69kg Nha-1 at both sites, and 30 and 40 kg P ha-1were found to be most profitable rates at Addis Alem and Tepi, respectively

Selectins Ligand Decorated Drug Carriers for Activated Endothelial Cell Targeting

New active particulate polymeric vectors based on branched polyester copolymers of hydroxy-acid and allyl glycidyl ether were developed to target drugs to the inflammatory endothelial cell surface. The hydroxyl and carboxyl derivatives of these polymers allow grafting of ligand molecules on the polyester backbones at different densities. A known potent nonselective selectin ligand was selected and synthesized using a new scheme. This synthesis allowed the grafting of the ligand to the polyester polymers, preserving its binding activity as assessed by docking simulations. Selectin expression on human umbilical cord vascular endothelial cells (HUVEC) was induced with the pro-inflammatory bacterial lipopolysaccharide (LPS) or with the nonselective inhibitor of nitric oxide synthase L-NAME. Strong adhesion of the ligand decorated nanoparticles was evidenced in Vitro on activated HUVEC. Binding of nanoparticles bearing ligand molecules could be efficiently inhibited by prior incubation of cells with free ligand, demonstrating that adhesion of the nanoparticles is mediated by specific interaction between the ligand and the selectin receptors. These nanoparticles could be used for specific drug delivery to the activated vascular endothelium, suggesting their application in the treatment of diseases with an inflammatory component such as rheumatoid arthritis and cancer