Slide 1

Plants and Environmental Toxicity http://www.greenpeace.org/raw/image_full/internation al/photosvideos/photos/the-river-in-midland-now-has- a.jpg The dose makes the poison Range of growth inhibition varies with plant species some more susceptible and others more tolerant Slide 2 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 Slide 3 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.jpghttp://www.nor.com.au/environm ent/clarencecatchment/images/ soil3.jpg Acidic granite soil in Australia Slide 4 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 Slide 5 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 Slide 6 What are toxic environments? Air Pollution http://www.transsib.ru/Photo/Vsib/5349.jpg Paper mill in Romania SO 2 (sulfur dioxide) NO x (nitrogen oxides) CO CO 2 O 3 (ozone) Hydrocarbons Ethylene Slide 7 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 Slide 8 What are toxic environments? Oxidative Damage H 2 O 2 (hydrogen peroxide) O 2 - (superoxide) Slide 9 What are the influences of toxins on plants? -inhibits acquisition of resources - water http://www.naturfoton.se/flora/flora/previous/Ch enopodiaceae/Suaeda-maritima-2.jpg Suaeda maritima Annual Sea Blight halophyte (salt- tolerant plant) Water uptake is inhibited as Soil solutes increase Compensate by synthesizing compensating Solutes in roots and leaves Slide 10 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 Slide 11 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 O 2 deficit (waterlogged soils) Slide 12 Resistance to Toxicity Avoidance http://www.kulak.ac.be/facult/wet/bi ologie/pb/kulakbiocampus/images/r/ 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 Slide 13 Resistance to Toxicity Avoidance alter soil pH If plant takes up cations (NH 4 + ), soil solution becomes more acid If plant takes up anions (NO 3 - ), soil solution becomes more basic So, under conditions of mineral toxicity (e.g. Al +3 ), plants will favor NO 3 - uptake Slide 14 Resistance to Toxicity Avoidance http://www.ars.usda.gov/images/docs/7647_7841/2005- X-PlantRoot.jpg Eastern Gama grass aerenchyma transports O 2 to the roots from the shoot when plants are flooded http://www.uri.edu/art sci/bio/plant_anatom y/26.html Slide 15 Resistance to Toxicity Avoidance - exclusion http://www.plantstress.com/Articles/toxicity_m/Tolerance_files/ image010.jpg Presence of Al +3 in soil solution opens anion channels that export malate (anion) into rhizosphere forms aluminum complex Slide 16 Resistance to Toxicity Localization http://www.biologie.uni-regensburg.de/Botanik/Schoenfelder/ Mesembryanthemum nodiflorum 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 Slide 17 Resistance to Toxicity - Excretion http://plantpath.unl.edu/llane/text/sa ltglands.htmlChenopodium quinoa salt glands http://online-media.uni- marburg.de/biologie/nutzpflanzen/bilde r/vb/chenopodium_quinoa.jpg Slide 18 Tolerance Great Dyke of Zimbabwe exposed rock formation rich in platinum and chromium with distinctive vegetation not found elsewhere Indigenous vegetation http://www.zimbabweflora.co.zw/species data/image-display.php http://earthobservatory.nasa.gov/ Slide 19 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 Slide 20 Phytoremediation http://www.landw.uni-halle.de/lfak/inst/iap/stockbuch/brsenf.jpg Brassica juncea Cd and Au (gold) accumulator)