Phyllosheric n fixation and factors affecting nodulation

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  • PhyllosphereThePhyllosphereis a term used inmicrobiologyto refer to the total above-ground portions of plants as habitat formicroorganisms.

  • Phyllosphere

    Rhizosphere

  • Caulosphere PhylloplaneAnthosphereCarposphere

    Divisions of Phyllosphere

  • Phyllospheric N fixationFixation of N on the surface of leaf.Leaf surface has been shown to provide appropriate conditions for colonization by microorganisms including diazotrophic bacteria that are able to fix atmospheric nitrogen N2.

  • ProcedureBacterial Entry

  • Multiplication

  • Colonization

  • Adhesion

  • Microbial Communities On Leaves

    Different genera of bacteria, filamentous fungi, yeasts, algae, and, less frequently, protozoa and nematodes.

    Filamentous fungi are present as sporesBacteria are the most abundant inhabitants of the phyllosphere.

  • Nitrogen fixing Bacteria Nitrogen fixing BlueGreen AlgaeAzotobacterPseudomonasPseudobacteriumErwinia SarcinaBeijerinckiaAnabaena CalothrixNostocScytonemaTolypothrix

  • SOME OF THE FUNGI AND ACTINOMYCETES FUNGUS

    ACTINOMYCETESAspergillus AlternariaCryptococcusCandidaPenicilliumFusariumVerticilliumStreptomycin

  • Rank of BNF

    N-FixersFixation (kg N/ha/year)Rhizobium legume50-600Cyanobacteria moss10-300Rhizophere associations5-25Free living0.2-25

  • N-fixation AssociationsLichens: cyanobacteria and fungiMosses and liverworts: some have associated cyanobacteriaAnabaena Azolla (Nostoc): cyanobacteria in stem of water fernGunerra Nostoc: cyanobacteria in nodule of dicot.

  • Acetobacter diazototrophicus lives in internal tissue of sugarcane and can fix 100-150 kg N/ha/year

    A few legumes (Susbenia rostreta) have root nodules as well as stem nodules. Stem nodules are capable of photosynthesis and N-fixation.

  • Research on the characteristics of microbial life in the phyllosphere is of great commercial importance to the agricultural industry for two reasonsUnderstanding the survival of plant disease-causing bacteria and fungi is vital for developing new ways to control their spread.

    There has been a recent rise in the number of food poisoning cases associated with fruit and vegetables contaminated with bacteria, such as Salmonella and E. coli.

  • Factors Affecting NodulationSoil chemistry and nutrientsAddition of nitrogenConcentration of inorganic nutrientsSoil temperatureLight and shadingRhizospheric microorganismsCO2concentration

  • The EndAny Question???

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