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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