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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/international/photosvideos/photos/the-river-in-midland-now-has-a.jpg.
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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/international/photosvideos/photos/the-river-in-midland-now-has-a.jpg
What are toxic environments? http://dcm2.enr.state.nc.us/ims/wetlands/salt_marsh.jpg Salt Marsh http://laser.cs.umass.edu:8000/~jcobleig/CrossCountry1/GreatSaltDesert.jpg Great Salt Desert between Salt Lake City and Reno Nevada
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/clarencecatchment/images/soil3.jpgAcidic granite soil in Australia
What are toxic environments? http://lamar.colostate.edu/~ippolito/biosolids/byers/4.jpg Application of sewage sludge (biosolids) in Colorado http://www2.nature.nps.gov/air/pubs/Core_Slides/images/slide006.jpg Lead and copper smelter El Paso
What are toxic environments? http://www.agry.purdue.edu/ext/corn/digital.img/2000/P6290030.jpg http://www1.crcsalinity.com/spa/photos.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.us/website/dar/ood/acidrain.gif http://www.wwf.it/summit/images/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/Chenopodiaceae/Suaeda-maritima-2.jpg Suaeda maritima Annual Sea Blight – halophyte (salt-tolerant 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 • Inhibition of enzyme activity • Inhibition of cell division • 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 ToxicityAvoidance • Phenology – grow when stress is less • 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/kulakbiocampus/images/r/
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. Al+3), plants will favor NO3- uptake
Resistance to ToxicityAvoidance http://www.uri.edu/artsci/bio/plant_anatomy/26.html 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
Resistance to ToxicityAvoidance - 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 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/Schoenfelder/ Mesembryanthemum nodiflorum
Resistance to Toxicity - Excretion http://online-media.uni-marburg.de/biologie/nutzpflanzen/bilder/vb/chenopodium_quinoa.jpg http://plantpath.unl.edu/llane/text/saltglands.htmlChenopodium quinoa salt glands
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/
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/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)