Biogeochemical Cycles Flashcards
Phosphate solubilisation is important because:
a) Bacteria cannot themselves access soluble forms of phosphate for efficient metabolism
b) Fungi need to access soluble forms of phosphate to support pathogenesis
c) Plants cannot access precipitated phosphate in the soil
d) Plants need to solubilise phosphate to support microbial communities in the rhizosphere
c) Plants cannot access precipitated phosphate in the soil
Phytate is a major plant storage compound for what element?
a) Sulphur
b) Carbon
c) Phosphate
d) Nitrogen
c) Phosphate
What chemical transformations are bacteria able to perform?
- Degradation of organic matter
- Disease suppression
- Disease causation
- Nutrient transformations inside roots
What type of fungi are Decomposers and what is their role?
Saprophytic fungi
* convert dead organic material into fungal biomass, CO2, and small molecules, such as organic acids
What type of fungi are Mutualists?
Mycorrhizal fungi
* Ectomycorrhizae
* Endomycorrhizae
What are the roles of Microalgae?
Convert solar energy, carbon dioxide, and other nutrients into sugars, proteins, and other complex organic compounds
What is Anabaena?
A genus of cyanobacteria
Where is nitrogen fixed in Anabaena?
Heterocysts
What does the sulphur content of soil consist of?
Sulphonates & Sulphate Esters
Crops synthesise which amino acids from the inorganic sulphur they take up?
Cysteine & Methionine
How do Rhizobacteria provide sulphates to the plant?
Enzymatically hydrolyse sulphonates and sulphate esters to release inorganic sulphur
What does Sulphate deficiency lead to in wheat?
Growth impairment and chlorosis
How do Phosphate-Solubilising Bacteria (PSB) solubilise unavailable forms of calcium-bound phosphorus?
By excreting organic acids while chelate calcium ions to bring phosphorus into solution
How does the production of the organic acids from calcium-bound phosphorus aid in solubilisation?
Decreases soil pH
What is the most frequently secreted organic acid used in bacterial phosphate solubilisation?
Gluconic
