Download Plants and Environmental Toxicity

Plants and Environmental Toxicity
“The dose makes the
poison”
Range of growth
inhibition varies with
plant species – some
more susceptible and
others more tolerant
http://www.greenpeace.org/raw/image_full/internation
al/photosvideos/photos/the-river-in-midland-now-hasa.jpg
What are toxic environments?
http://dcm2.enr.state.nc.us/ims/wetlan
ds/salt_marsh.jpg
Salt Marsh
http://laser.cs.umass.edu:8000/~jc
obleig/CrossCountry1/GreatSaltDe
sert.jpg
Great Salt Desert between Salt
Lake City and Reno Nevada
What are toxic
environments?
http://forest.moscowfsl.wsu.edu/smp/pho
tos/ltsp_bc_calcareous_l.jpg
Calcareous soil in British Columbia
http://www.nor.com.au/environm
ent/clarencecatchment/images/
soil3.jpg Acidic granite soil in
Australia
What are toxic
environments?
http://www2.nature.nps.gov/air/pubs/Cor
e_Slides/images/slide006.jpg
Lead and copper smelter El Paso
http://lamar.colostate.edu/~ippolito/bi
osolids/byers/4.jpg
Application of sewage sludge
(biosolids) in Colorado
What are toxic environments?
http://www.agry.purdue.edu/ext/corn/
digital.img/2000/P6290030.jpg
http://www1.crcsalinity.com/spa/ph
otos.htm
Puccinellia growing in
waterlogged conditions in
Australia
What are toxic environments?
Air Pollution
SO2 (sulfur dioxide)
NOx (nitrogen oxides)
CO
CO2
O3 (ozone)
Hydrocarbons
Ethylene
http://www.transsib.ru/Photo/Vsib/5349.jpg
Paper mill in Romania
Acid Rain
http://www.dec.state.ny.u
s/website/dar/ood/acidrai
n.gif
http://www.wwf.it/summit/imag
es/19061_germany%20Acid%
20rain.jpg
Acid rain damaged forest in
Germany
What are toxic environments?
Oxidative Damage
H2O2 (hydrogen peroxide)
O2- (superoxide)
What are the influences of toxins on plants?
-inhibits acquisition of resources - water
Water uptake is inhibited
as
Soil solutes increase
Compensate by
synthesizing
compensating
Solutes in roots and
leaves
http://www.naturfoton.se/flora/flora/previous/Ch
enopodiaceae/Suaeda-maritima-2.jpg
Suaeda maritima
Annual Sea Blight – halophyte (salttolerant plant)
What are the influences of toxins on plants?
-inhibits acquisition of resources – carbon/energy
http://www.cbesurvey.org/aplv/panek/ozone.htm
Ozone impacts woody species by increasing
stomatal resistance and decreasing
photosynthesis
What are the influences
of toxins on plants?
-inhibits utilization of
resources
1. Inhibition of enzyme activity
2. Inhibition of cell division
3. Wasteful use of resources
http://wheat.pw.usda.gov/ggpages/wheatpests.html
Salt stress in wheat
Plant roots produce ethanol
under conditions of O2
deficit (waterlogged soils)
Resistance to Toxicity
Avoidance
1. Phenology – grow
when stress is less
http://www.kulak.ac.be/facult/wet/bi
ologie/pb/kulakbiocampus/images/r/
2. Timing – Limonium
vulgare (Common
Sea Lavender) –
seeds germinates
best when treated
with sea water
followed by fresh
water
Resistance to Toxicity
Avoidance – alter soil pH
If plant takes up cations
(NH4+), soil solution becomes
more acid
If plant takes up anions
(NO3-), soil solution becomes
more basic
So, under conditions of
mineral toxicity (e.g. Al+3),
plants will favor NO3- uptake
Resistance to
Toxicity
Avoidance
http://www.ars.usda.gov/images/docs/7647_7841/2005X-PlantRoot.jpg
Eastern Gama grass aerenchyma transports O2 to
the roots from the shoot when plants are flooded
http://www.uri.edu/art
sci/bio/plant_anatom
y/26.html
Resistance to Toxicity
Avoidance - exclusion
Presence of Al+3 in soil
solution
opens anion channels
that export malate (anion)
into rhizosphere – forms
aluminum complex
http://www.plantstress.com/Articles/toxicity_m/Tolerance_files/
image010.jpg
Resistance to Toxicity
Localization
Toxic minerals (Al, Cd)
are accumulated in root
vacuoles by halophytes
to prevent dehydration
of the cytoplasm, nonreactive solutes (amino
acid proline) are
synthesized
http://www.biologie.uni-regensburg.de/Botanik/Schoenfelder/
Mesembryanthemum nodiflorum
Resistance to Toxicity - Excretion
http://online-media.unimarburg.de/biologie/nutzpflanzen/bilde
r/vb/chenopodium_quinoa.jpg
http://plantpath.unl.edu/llane/text/sa
ltglands.htmlChenopodium
quinoa salt glands
Tolerance
Indigenous vegetation
http://www.zimbabweflora.co.zw/species
data/image-display.php
http://earthobservatory.nasa.gov/
Great Dyke of Zimbabwe –
exposed rock formation rich
in platinum and chromium
with distinctive vegetation not
found elsewhere
Phytoremediation
Can plants be used to clean up contaminated
soils?
Succesful phytoremediation systems need
plants that:
1. Can survive on contaminated soil
2. Can absorb toxins into roots
3. Can transport toxins to shoots for harvest
and removal
4. Have a high growth rate for high efficiency
clean-up
http://www.wits.ac.za/museums/herbarium/students/sanwil.htm
Berkheya coddii –hyperaccumulator of nickel
Phytoremediation
http://www.landw.uni-halle.de/lfak/inst/iap/stockbuch/brsenf.jpg
Brassica juncea – Cd and Au (gold) accumulator)