Phyllosphere

• The Phyllosphere is a term used in microbiology to refer to the total above-ground portions of plants as habitat for microorganisms.

Phyllosphere

Rhizosphere

• Caulosphere • Phylloplane• Anthosphere• Carposphere

Divisions of Phyllosphere

Phyllospheric N fixation

• Fixation 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.

Procedure

• Bacterial 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 spores• Bacteria are the most abundant

inhabitants of the phyllosphere.

Nitrogen –fixing Bacteria Nitrogen –fixing Blue

Green Algae

AzotobacterPseudomonasPseudobacteriumErwinia SarcinaBeijerinckia

Anabaena Calothrix Nostoc Scytonema Tolypothrix

SOME OF THE FUNGI AND ACTINOMYCETES

• FUNGUS ACTINOMYCETES

Aspergillus AlternariaCryptococcusCandidaPenicilliumFusariumVerticillium

Streptomycin

Rank of BNFN-Fixers Fixation (kg N/ha/year)

Rhizobium legume 50-600

Cyanobacteria – moss 10-300

Rhizophere associations 5-25

Free living 0.2-25

N-fixation Associations

• Lichens: cyanobacteria and fungi• Mosses and liverworts: some have

associated cyanobacteria• Anabaena Azolla (Nostoc):

cyanobacteria in stem of water fern• Gunerra 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 reasons

Understanding 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 Nodulation

• Soil chemistry and nutrients• Addition of nitrogen• Concentration of inorganic nutrients• Soil temperature• Light and shading• Rhizospheric microorganisms• CO2 concentration

The End

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