9 research outputs found
A mikrorespirációs (MicroResp<sup>TM</sup>) módszer alkalmazása apajpusztai szikes talajok mikrobaközösségeinek katabolikus aktivitás mintázatának vizsgálatára
A talajok hazai Ă©s nemzetközi kutatásában egyre nagyobb szerepet kap a talajok mikrobiĂłtájának vizsgálata. Hazai viszonylatban szikes talajokon eddig kevĂ©s ilyen irányĂş kutatás törtĂ©nt. Kutatásunkban kiskunsági szikes talajok mikrobaközössĂ©geinek katabolikus aktivitás mintázatát vizsgáltuk ApajpusztárĂłl származĂł mintákon. A mintavĂ©telhez nĂ©gy, a szikesedĂ©s kĂĽlönbözĹ‘ fázisaira jellemzĹ‘ növĂ©nyzettel rendelkezĹ‘ terĂĽletet választottunk ki (szoloncsák vaksziknövĂ©nyzet, kiskunsági szikfoknövĂ©nyzet, ĂĽrmös szikespuszta Ă©s fĂĽves szikespuszta), ezek terĂĽletĂ©rĹ‘l a talaj mikrobiolĂłgiai szempontbĂłl legaktĂvabbnak tekintett 0-10 cm-es rĂ©tegĂ©t mintáztuk.
A minták néhány fontosabb talajtani paraméterét meghatároztuk (szemcseösszetétel, pH, só-, humusz- és mésztartalom, valamint néhány fontosabb tápelem mennyisége). A négy eltérő növényzetű terület között a talajtani paramétereik alapján is jelentős különbségeket tapasztaltunk.
A minták mikrobiolĂłgiai aktivitását az itthon mĂ©g kevĂ©ssĂ© ismert mikrorespiráciĂłs (MicroRespTM) mĂłdszerrel vizsgáltuk. Ennek során a talajmintákhoz 23 kĂĽlönbözĹ‘ szerves szubsztrátot adtunk, Ă©s az általuk indukált lĂ©gzĂ©si válaszon keresztĂĽl mĂ©rtĂĽk, hogy az egyes talajminták mikrobaközössĂ©gei milyen mĂ©rtĂ©kben kĂ©pesek hasznosĂtani az egyes szubsztrátokat. Az Ăgy kapott, közössĂ©gre jellemzĹ‘ katabolikus aktivitás mintázatokat fĹ‘komponens elemzĂ©ssel Ă©s kanonikus korreszpondancia elemzĂ©ssel Ă©rtĂ©keltĂĽk.
EredmĂ©nyeink alapján a mikrorespiráciĂłs mĂłdszer egyĂ©rtelműen alkalmas az általunk vizsgált talajok mikrobiĂłtájának elkĂĽlönĂtĂ©sĂ©re. Az egyes minták katabolikus aktivitás mintázatai közötti kĂĽlönbsĂ©gek egybevágtak a minták közötti, talajfizikai Ă©s —kĂ©miai tulajdonságban megfigyelt eltĂ©rĂ©sekkel.
A kutatást az OTKA (K 108572) támogatta.
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The study of the soil microbiota is becoming more and more important both in Hungarian researches and internationally. However, there were only a few microbiological studies in Hungary that focused on saline and sodic soils. In this paper, we report the results of the study of catabolic activity profiles of microbial communities inhabiting saline soils at Apajpuszta, Kiskunság NP, Hungary. Four sampling sites were chosen, that had a specific vegetation types, characteristic to different stages of soil salinization: 1) Saline bare spot (signed by L), or Lepidio crassifolii-Camphorosmetum annuae, 2) Puccinellia sward (signed by P), or Lepidio crassifolii-Puccinellietum limosae, 3) Artemisia Alkali steppe (signed by A), or Artemisio santonici-Festucetum pseudovinae, and 4) Short-grass pasture or Achillea Alkali steppe (signed by F), or Achilleo setaceae-Festucetum pseudovinae. From these areas, we took samples from the 0-10 cm layer, which is usually considered as the most microbiologically active part of soils.
Some of the most important physical and chemical parameters of the soil samples were measured (soil texture, pH, salt content, humus content, carbonate content, and the concentration of some nutrients). We found that the four sampling sites had quite distinct soil properties, and could be separated by PCA based on the abiotic parameters examined.
The catabolic activity of the soil samples was measured by the MicroResp method, which is a relatively new method in Hungary. We added 23 organic substrates to the soils in a deep-well microplate and measured rate of respiration induced by each substrate. The catabolic activity profiles (or community level physiological profiles - CLPPs) of the samples were than analyzed by PCA. Based on our results, we conclude that the MicroResp method was able to distinguish between the microbial communities of the four sites. Results of PCA from the environmental variables and from the CLPPs showed a similar pattern of separation, indicating a strong potential relationship between the two
Effect of Rhizobium and AM fungi inoculation on soybean
Symbiotic effectivity of two- and tripartite symbiotic agents was investigated in a pot experiment on three soybean (Glycine max L. Merr.) cultivars with special regard to compatibility. Host plants were single and co-inoculated with two Bradyrhizobium japonicum strains and two commercial arbuscular mycorrhizal fungal (AMF) products. Significant differences were found in infectivity and effectivity of the microsymbionts. While infectivity of AMF inocula was very poor, the benefits of AMF treatments were more expressed than that of the rhizobial ones. In case of commercial AMF inoculants we should also check the effect of the ingredients of the explain medium.Keywords: Bradyrhizobium sp., arbuscular mycorrhizal fungi, soybean, host compatibility, biomas
Alphaproteobacteria communities depend more on soil types than land managements
Soil properties and agricultural practices take a joint effect on the communities of soil bacteria. The aim of the present study was to survey Alphaproteobacterial communities as possible indicators of soil quality considering clay, loamy and sandy soils under conventional and organic farming. Alphaproteobacteria community composition were analysed by 16S rRNA gene with nested-PCR (polymerase chain reaction) and denaturing gradient gelelectrophoresis (DGGE). Sequencing of partial 16S rRNA gene from the DGGE bands were performed. Conventional and organic farming resulted in significant differences in chemical properties of soils. According to the results community fingerprints were separated into groups depending on soil types and farming systems. This separation can be attributed mostly to soil pH, AL-P2O5,-K2O. The analysed sequences were identified as soil bacteria which could play the main role in nitrogen fixing, mineralisation and denitrification. The highest diversity index was revealed from the organic farming at sandy texture site, where mainly Mesorhizobium sp. and Rhizobium sp. were detected. The soil type and actual crop could have a stronger impact on the soil bacterial composition than the management