Benefits of inoculation with azotobacter in the growth and production of tomato and peppers

The aim of this research was to investigate the effects of Azotobacter chroococcum in tomato and pepper growth and production by using two types of inoculation - seed inoculation and seedling inoculation. The effect of inoculation was observed thirty days after sowing, thirty days after transplanting, and in the phase of technological maturity. The following were measured: height of the plants, dry matter of the plants and number and the weight of the fruits. Inoculation had a positive effect on these in both plants. With tomato, better results were achieved when seedlings were inoculated. With pepper, the length of the plant and the dry matter were greater with seedling inoculation, whereas the number and the weight of the fruits were greater with seed inoculation

Mikroorganizmi u rizosferi - uloga i značaj u održivoj poljoprivredi

Rhizosphere is the zone around the plant root, including the root, the soil on the root and the surrounding soil that is influenced by the roots. Microorganisms that live in that complex habitat affect the health of plants and their yield. Knowledge of the composition and quantity of organic compounds that are released by roots provides insight into the chemical and biological processes that occur in the rhizosphere. Each plant species selects its own specific bacterial community from a reservoir of bacteria present in the soil or on the seed. Using natural resources in a sustainable microbial agricultural production is based on the multiplication of active species and strains of microorganisms in artificial conditions and returning in their natural environment - soil where these microorganisms intensify the appropriate processes, produce more plant nutrients, stimulate the growth of plants and protect them from pathogens and toxic substances. These microorganisms may partially or completely replace mineral fertilizers and pesticides.Dat je pregled biologije rizosfere, definicija rizosfere, značaj korenskih izlučevina, interakcija mikroorganizama, njihova dinamika u rizosferi sa posebnim naglaskom na bakterije. Istaknut je značaj korisnih mikroorganizama za održivu poljoprivrednu proizvodnju primenom biofertilizatora i rizobakterija promotora biljnog rasta (PGPR). Mikroorganizmi koji žive u kompleksnom staništu - rizosferi utiču na zdravlje biljaka, njihov prinos i kvalitet. Proučavanje rizosfere vodi do mnogih korisnih interakcija. Neki metaboliti mikroorganizama kao što su antibiotici i toksini su osnovni faktori u determinaciji interakcija biljka-mikroorganizam. Mikrobni enzimi takođe igraju značajnu ulogu. Odnosi između korena biljaka i mikroorganizama predmet su interesovanja molekularnih biologa, mikrobiologa i biohemičara širom sveta

Mikrobiološke transformacije jedinjenja fosfora i sumpora u kiselim zemljištima

The dynamics of phosphorus and sulphur in soil is closely related to the dynamics of the biological cycle in which microorganisms play a central role. There is not much microbiological activity in acid soils because aerobes are scarce, rhizosphere is restricted to the shallow surface layer, and the biomass of microorganisms decreases with higher acidity. The aim of the research was to investigate the number of microorganisms, which decompose organic and inorganic phosphorus compounds and organic sulphur compounds in calcocambisol, luvisol, and pseudogley. The following parameters were determined in the soil samples: pH in H2O and in 1MKCl; the content of CaCO3 (%); humus content (%), nitrogen content (%); the content of physiologically active phosphorus and potassium (mg P2O5/100g of soil; mg K2O/100g of soil). The number of microorganisms was determined by the method of agar plates on appropriate nutrient media: the number of microorganisms solubilizing phosphates on a medium by Muramcov; the number of microorganisms that decompose organic phosphorus compounds on a medium with lecithin; and the number of microorganisms that transform organic sulphur compounds on a medium by Baar. All three types of soil are acid non-carbonate soils with a low level of available phosphorus and a more favorable amount of potassium, nitrogen, and humus. The largest number of bacteria, which transform organic phosphorus compounds, was found in calcocambisol. The largest number of phosphate solubilizing bacteria was recorded in pseudogley, whereas the largest number of phosphate solubilizing fungi was recorded in calcocambisol. The largest number of bacteria, which transform organic sulphur compounds, was recorded in pseudogley.Dinamika fosfora i sumpora u zemljištu tesno je povezana sa dinamikom biološkog ciklusa u kojem mikroorganizmi imaju centralnu ulogu. Mikrobiološka aktivnost u kiselim zemljištima nije velika, jer su potisnuti aerobi, rizosfera je ograničena na plitku površinsku zonu, a sa povećanjem kiselosti smanjuje se i biomasa mikroorganizama. Cilj ovih istraživanja je bio da se ispita zastupljenost mikroorganizama koji razlažu organska i neorganska jedinjenja fosfora i organska jedinjenja sumpora u kalkokambisolu, luvisolu i pseudogleju. U uzorcima zemljišta određeni su sledeći parametri: reakcija zemljišta (pH) u H2O i u 1MKCl; sadržaj CaCO3 (%); sadržaj humusa (%); sadržaj azota (%); sadržaj fiziološki aktivnog fosfora i kalijuma (mg P2O5/100g zemljišta; mg K2O/100g zemljišta). Broj mikroorganizama određivan je metodom agarnih ploča na odgovarajućim selektivnim hranjivim podlogama: broj mikroorganizama koji razlažu fosfate na podlozi po: Muramcov, broj mikroorganizama koji razlažu organska fosforna jedinjenja na podlozi sa lecitinom, a broj mikroorganizama koji transformišu organska jedinjenja sumpora na podlozi po Baar-u. Sva tri tipa zemljišta spadaju u grupu kiselih beskarbonatnih zemljišta, sa niskim sadržajem pristupačnog fosfora i povoljnijim sadržajem kalijuma, azota i humusa. Najveći broj bakterija koje transformišu organska jedinjenja fosfora utvrđen je u kalkokambisolu. Najveći broj bakterija koje razlažu fosfate utvrđen je u pseudogleju, a najveći broj gljiva koje razlažu fosfate u kalkokambisolu. Najveći broj bakterija koje transformišu organska jedinjenja sumpora utvrđen je u pseudogleju

Uticaj fitaze mikrobioloskog porekla na proizvodne rezultate i karakteristike kostiju prasadi

The 31 day long trial included 24 Yorkshire piglets divided into three groups. Before weaning, the piglets were given the experimental diets in a 7-day adjustment period. During this period as well as for 22 days following, the piglets were fed on diets containing 22% CP and then diets containing 20% CP for the remaining 19 days. The desired level of phosphorus in the diet for the control group and experimental group III was achieved by the addition of dicalcium phosphate, while the diet for group II was without added dicalcium phosphate. In addition the, diets for groups II and III were enriched with crude phytase (produced by growing an isolate of Aspergillus awamori) in an amount sufficient to provide 800 FU/kg. Performance and state of health were monitored during the trial and at the end the piglets were killed for collection of bone samples. Growth performance was improved by adding microbial phytase. Ash and calcium content in the tibia showed no statistical differences between the groups, while content of phosphorus was significantly increased in both groups fed added phytase in the diet. The length and width of the tibia and the intensity of its shadow indicated normal physiological processes in bone formation and ossification. The best ossification was obtained in the first experimental group, based on almost invisible nutrition channels inside the thick shadow of compacta, as well as the homogenous appearance of tibiae spongiosa in the mid diaphysis area.Ogled je izveden na 24 odbijene Jorkšir prasadi podeljenih u tri grupe, a trajao je 31 dan. U pripremnom periodu od 7 dana pre odbijanja, kao i tokom naredna 22 dana prasad su hranjena smešom sa 22% proteina, a zatim smešom sa 20% proteina do kraja ogleda. Planirani nivoi fosfora u I i III grupu postignuti su dodavanjem dikalcijum fosfata, dok su smeše za ishranu II grupe prasadi bile bez dodatog dikalcijum fosfata. Smešama za K i O-ll grupu prasadi dodata je sirova fitaza (izolovana iz gljivica Aspergillus awamori) u količini koja je obezbedila 800 FU/kg hrane. Tokom ogleda praćeni su proizvodni rezultati i zdravstveno stanje, a na kraju ogleda izvršeno je žrtvovanje prasadi u cilju uzimanja uzoraka kostiju za predviđena ispitivanja. Proizvodni rezultati su bili poboljšani korišćenjem fitaze mikrobijalnog porekla. Razlike u sadržaju pepela i kalcijuma tibije nije se statistički razlikovao, dok je sadržaj fosfora signifikantno rastao u grupama sa dodatom fitazom mikrobijalnog porekla. Rezultati morfometrijskih i radiografskih ispitivanja ukazala su na normalne fiziološke procese osifikacije kostiju. Na osnovu dobijenih rezultatanajbolje izražen proces osifikacije kostiju bio je u prvoj oglednoj grupi prasadi

Effects of plant growth promoting rhizobacteria on maize in greenhouse and field trial

The aim of the study was to investigate ability of Pseudomonas sp. Q4b, Bacillus sp. Q5a and Azotobacter chroococcum strain 8 to enrich a population of plant growth promoting rhizobacteria (PGPR) in rhizosphere and thus enhance maize growth (Zea mays L.). Experiments were carried out under greenhouse and field conditions, on a chernozem soil. In vitro screening for PGP properties showed significant difference between indole-3-acetic acid (IAA) and siderophores production and phosphosolubilization between Pseudomonas sp. Q4b and Bacillus sp. Q5a. Pseudomonas was estimated as a better producer of hydrogen cyanide (HCN) and siderophores than Bacillus. Bacterial treatments had a significant effect on the number of investigated microbial groups in rhizosphere, and maize growth and yield. Co-inoculation had an advantage compared to single inoculation, while in case of single strains, better effects were achieved in Pseudomonas and Azotobacter treatments. Inoculation increased the number of azotobacters (103.25%), pseudomonads (82.29%) and aerobic spore-forming bacteria (52.65%) as well as height (17.15%) and dry weight (35.48%) of maize plants. The highest plant height was recorded in treatment with Pseudomonas and Bacillus. The highest dry weight and yield were recorded in the treatment with mixture of these three strains

Značaj i efekat primene PGPR na mikrobiološku aktivnost u rizosferi kukuruza

Microorganisms are involved in the formation of soil fertility, both potential and effective. They facilitate the processes of humification and dehumification and play a key role in the cycling of nutrients - macro and microelements. Rhizosphere is the soil in direct contact with plant roots and influenced by plant exudates. Root exudates of maize significantly affect the composition and abundance of microorganisms in the rhizosphere. Bio-fertilizers are microbial fertilizers composed of highly effective strains of bacteria, algae and fungi isolated from soil. Their application activates microbial processes that secure a better and steadier supply of plants with nitrogen, phosphorus, potassium and some micronutrients. The application of PGPR-containing biofertilizers reduces the need for expensive nitrogen fertilizers, facilitates phosphorus uptake by plants and affects the direction and dynamics of microbial processes.Mikroorganizmi učestvuju u stvaranju plodnosti zemljišta, kako potencijalne tako i efektivne. Mikroorganizmi omogućavaju odvijanje procesa humifikacije i dehumifikacije i zauzimaju centralno mesto u kruženju neophodnih hranljivih makro i mikroelemenata. Zona zemljišta koja okružuje korenov sistem biljaka i pod uticajem je njegovih izlučevina može se definisati kao rizosfera. Svojim korenskim izlučevinama kukuruz može značajno da utiče na sastav i brojnost mikroorganizama u rizosferi. Biofertilizatori su mikrobiološka đubriva koja sadrže selekcionisane visoko efektivne sojeve bakterija, algi i gljiva izolovane iz zemljišta. Njihovim unošenjem u zemljište aktiviraju se odgovarajući mikrobiološki procesi koji omogućavaju bolje i ravnomernije snabdevanje biljaka azotom, fosforom i kalijumom, kao i nekim mikroelementima. Primenom biofertilizatora koji sadrže rizobakterije promotore biljnog rasta - PGPR (Plant Growth Promoting Rhizobacteria) smanjuje se upotreba skupih azotnih đubriva, omogućava se biljci lakše usvajanje fosfora i utiče na pravac i dinamiku mikrobioloških procesa

Genodiverzitet dominantnih Rhizobium leguminosarum bv. Trifolii izolovanih iz 11 tipova zemljišta Srbije

Rhizobium leguminosarum bv. trifolii is microsymbiont Trifolium pratense and Trifolium repens, which are very important legumes in Serbia. The natural nodulating population of those bacteria was collected and estimated biodiversity distribution by monitoring dominant genotypes of these bacteria. The population of Rhizobium leguminosarum bv. trifolii were collected from 50 marked locations of 11 types of soil in Serbia. 437 natural isolates, rescued from nodules of Trifolium repens or Trifolium pratense, were analyzed by phenotypic approach. We obtained 156 different isolates on the basis of differences in their IAR - intrinsic antibiotic resistance (five antibiotics) and HMT- heavy methal tolerance (five heavy metals). We investigated 56 dominant isolates with more than three differences in IAR-HMT patterns by REP-PCR and RAPD fingerprinting (AP10 and SPH 1 primers). The results showed genodiversity of dominant Rhizobium leguminosarum bv. trifolii field isolates and offered the possibility to assess their changes on marked locations during time and under different environmental conditions and geographical distribution.Rhizobium leguminosarum bv. trifolii je mikrosimbiont Trifolium pratense i Trifolium repens, veoma značajnih leguminoza u Srbiji. Kolekcionisana je prirodna populacija ovih simbiotskih azotofiksatora i procenjen nivo biodiverziteta analizom dominantnih izolata ovih bakterija. Populacija Rhizobium leguminosarum bv. trifolii je prikupljena sa 50 markiranih lokacija sa 11 tipova zemljišta u Srbiji. 437 autohtonih izolata, izolovanih iz nodula Trifolium repens ili Trifolium pratense, analizirano je fenotpskim metodama. Dobijeno je 156 različitih izolata na osnovu razlika u osetljivosti na pet antibiotika (IAR - intrinsic antibiotic resistance) i tolerantnosti na pet teških metala (HMT- heavy methal tolerance). Utvrđeno je prisustvo 56 dominantnih izolata sa značajnim razlikama u IAR-HMT profilu i za reprezentativne izolate grupe urađen REP-PCR i RAPD fingerprinting (AP10 i SPH 1 prajmerima). Rezultati su pokazali visok stepen genodiverziteta dominantnih izolata Rhizobium leguminosarum bv. trifolii omogućili praćenje promena diverziteta i zastupljenosti na markiranim lokacijama tokom vremena i pri različitim uslovima životne sredine i geografske rasprostranjenosti

Diversity Rhizobium leguminosarum bv. trifolii field population from chernozem, pseudogley and hydromorphic black soil

The presence of indigenous nitrogen fixing microsymbionts of leguminous plants in different type of soil are of great agricultural and environmental significance. To achieve beneficial effect of plant inoculation we need consider the characteristics of rhizobial field population. To investigate the diversity level of rhizobial population, we isolated 80 indigenius Rhizobium leguminosarum bv. trifolii from soil type chernozem, 27 from hydromorphic black soil and 92 from pseudogley. High level of genetic diversity was found among indigenous Rhizobium leguminosarum bv. trifolii population. Diversity of indigenous plant isolates from two types of soil in Serbia will be monitoring in the different enviromental conditions