Plants and Environmental Toxicity

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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/internati
onal/photosvideos/photos/the-river-in-midland-now-
has-a.jpg
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What are toxic environments?
http//dcm2.enr.state.nc.us/ims/wetlands/salt_mars
h.jpg Salt Marsh
http//laser.cs.umass.edu8000/jcobleig/CrossCoun
try1/GreatSaltDesert.jpg Great Salt Desert
between Salt Lake City and Reno Nevada
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What are toxic environments?
http//forest.moscowfsl.wsu.edu/smp/photos/ltsp_bc
_calcareous_l.jpg Calcareous soil in British
Columbia
http//www.nor.com.au/environment/clarencecatchmen
t/images/soil3.jpg Acidic granite soil in
Australia
4
What are toxic environments?
http//lamar.colostate.edu/ippolito/biosolids/bye
rs/4.jpg Application of sewage sludge
(biosolids) in Colorado
http//www2.nature.nps.gov/air/pubs/Core_Slides/im
ages/slide006.jpg Lead and copper smelter El Paso
5
What are toxic environments?
http//www.agry.purdue.edu/ext/corn/digital.img/20
00/P6290030.jpg
http//www1.crcsalinity.com/spa/photos.htm Puccin
ellia growing in waterlogged conditions in
Australia
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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
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Acid Rain
http//www.dec.state.ny.us/website/dar/ood/acidrai
n.gif
http//www.wwf.it/summit/images/19061_germany20Ac
id20rain.jpg Acid rain damaged forest in Germany
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What are toxic environments?Oxidative Damage
H2O2 (hydrogen peroxide) O2- (superoxide)
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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/Chen
opodiaceae/Suaeda-maritima-2.jpg Suaeda
maritima Annual Sea Blight halophyte
(salt-tolerant plant)
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What are the influences of toxins on
plants?-inhibits acquisition of resources
carbon/energy
http//www.cbesurvey.org/aplv/panek/ozone.htm Ozo
ne impacts woody species by increasing stomatal
resistance and decreasing photosynthesis
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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 S
alt stress in wheat
Plant roots produce ethanol under conditions of
O2 deficit (waterlogged soils)
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Resistance to ToxicityAvoidance

1. Phenology grow when stress is less
2. Timing Limonium vulgare (Common Sea Lavender)
   seeds germinates best when treated with sea
   water followed by fresh water

http//www.kulak.ac.be/facult/wet/biologie/pb/kula
kbiocampus/images/r/
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Resistance to ToxicityAvoidance 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. Al3),
plants will favor NO3- uptake
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Resistance to ToxicityAvoidance
http//www.uri.edu/artsci/bio/plant_anatomy/26.htm
l
http//www.ars.usda.gov/images/docs/7647_7841/2005
-X-PlantRoot.jpg Eastern Gama grass aerenchyma
transports O2 to the roots from the shoot when
plants are flooded
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Resistance to ToxicityAvoidance - exclusion
Presence of Al3 in soil solution opens anion
channels that export malate (anion) into
rhizosphere forms aluminum complex
http//www.plantstress.com/Articles/toxicity_m/Tol
erance_files/image010.jpg
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Resistance to ToxicityLocalization
Toxic minerals (Al, Cd) are accumulated in root
vacuoles by halophytes to prevent dehydration of
the cytoplasm, non-reactive solutes (amino acid
proline) are synthesized
http//www.biologie.uni-regensburg.de/Botanik/Scho
enfelder/ Mesembryanthemum nodiflorum
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Resistance to Toxicity - Excretion
http//plantpath.unl.edu/llane/text/saltglands.htm
lChenopodium quinoa salt glands
http//online-media.uni-marburg.de/biologie/nutzpf
lanzen/bilder/vb/chenopodium_quinoa.jpg
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Tolerance
Indigenous vegetation http//www.zimbabweflora.co.
zw/speciesdata/image-display.php
Great Dyke of Zimbabwe exposed rock formation
rich in platinum and chromium with distinctive
vegetation not found elsewhere
http//earthobservatory.nasa.gov/
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Phytoremediation

• Can plants be used to clean up contaminated
  soils?
• Succesful phytoremediation systems need plants
  that
• Can survive on contaminated soil
• Can absorb toxins into roots
• Can transport toxins to shoots for harvest and
  removal
• Have a high growth rate for high efficiency
  clean-up

http//www.wits.ac.za/museums/herbarium/students/s
anwil.htm Berkheya coddii hyperaccumulator of
nickel
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Phytoremediation
http//www.landw.uni-halle.de/lfak/inst/iap/stockb
uch/brsenf.jpg Brassica juncea Cd and Au (gold)
accumulator)