week 12 Flashcards
(25 cards)
What are the two most listing elements to terrestrial vegetation?
Nitrogen (N) and phosphorus(P)
Where do plants take up essential nutrients?
through the roots
What do elements undergo for nutrients to be available for plant uptake?
mineralisation
What do the pH and redox state affect?
availability of nutrients for plants
Land plants key features?
- Vascular System (wood/lignin/cellulose)
- Roots (wood/lignin/cellulose)
- Structure (wood/lignin/cellulose)
- Storage (starch)
N:P ratios of terrestrial plants are similar to the Redfield ratio found in?
marine phytoplankton. But there is a lot more C.
What does the N/P ratio do as it heads towards the equator?
increases
nutrients and C leaves in Australian foliage?
Low on nutrients
High on C
What are the effects of Excess C?
Affects pollination
Affects herbivory
Sclerophylly
What is Sclerophylly?
Hard, tough, stiff leaves: efficient biomass partitioning in stressful environments, increased likelihood of leaves reaching the optimal lifespan.
Ideal leaf traits
Thin large low C:N ratio high turgor high photosynthetic capacity
What are heavy metals?
Heavy metals are elements that exhibit metallic properties such as ductility, malleability, conductivity, cation stability, and ligand specificity. Relatively high density and high relative atomic weight with an atomic number greater than 20
What happens when heavy metals concentrations get above 0.1%?
With the exception of Fe, all heavy metals above a concentration of 0.1% in the soil become toxic to most plants
What is Tolerance?
the ability to survive, grow and reproduce in areas with high levels of heavy metal in the soil
What are the two different tolerance methods?
Accumulation
Exclusion– (most plants)
Key details Accumulation?
(1) root uptake to the cell (not exclusion)
(2) root-to-shoot translocation (move the
metal from the root to the shoot)
(3) Heavy metal binding to the cell walls and/or cell exudates
(4) chelation in the cytosol and/or
sequestration in vacuoles,
What are hyper accumulators?
- strongly enhanced rate of heavy metal uptake
- faster root-to-shoot translocation
- greater ability to detoxify and sequester heavy metals in leaves
What are the criteria for a hyper accumulator?
-the concentration of metal in the shoot must be higher than 0.1% for Al, As, Co, Cr, Cu, Ni, and Se, higher than 0.01% for Cd, and higher than 1.0% for Zn
-the ratio of shoot to root concentration must be consistently higher than 1; this indicates the capability to transport metals from roots to shoot and the existence of
hypertolerance ability
-the ratio of shoot to root indicates the degree of plant metal uptake (a higher ratio indicates more accumulation)
What is Phytoremediation?
Using hyperaccumlators ti take up heavy metals improving the soil
What is Phytoremediation used for?
Wastewater treatment, heavy metals and metalloids, organic pollutants (TNT, PCB) and radionucleotides.
What are the advantages of Phytoremediation?
Perceived to occur via natural processes
Aesthetically pleasing
Inexpensive
What are the Limitations of Phytoremediation?
Effective only where contamination of soil and water is shallow (< 5 m)
Takes time and affected by growing conditions
Can transfer toxins up the food chain
Why did Phytoremediation fail at Fukushima?
Genetic differences between the sunflower genotypes used in the Ukraine and Japan could account for the success and failure of phytoremediation projects in these countries
What is Phyto (biogeochemical, geo-botanical) exploration?
using plants for mapping geology, mineral deposits, petroleum seeps
