C am.ppt

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  • ^C.Michael Hogan. 2011. Respiration. Encyclopedia of Earth. Eds. Mark McGinley & C.J.cleveland. National council for Science and the Environment. Washington DC^Ranson S. L.; Thomas M (1960). "Crassulacean acid metabolism". Annual Rev Plant Physiol11 (1): 81–110. doi:10.1146/annurev.pp.11.060160.000501.^ abc Herrera, A. (2008), "Crassulacean acid metabolism and fitness under water deficit stress: if not for carbon gain, what is facultative CAM good for?", Annals of Botany103 (4): 645–653, doi:10.1093/aob/mcn145^ Ting, I P (1985). "Crassulacean Acid Metabolism". Annual Review of Plant Physiology36 (1): 595. doi:10.1146/annurev.pp.36.060185.003115.^ Raven, JA; Edwards, D. (2001). "Roots: evolutionary origins and biogeochemical significance". Journal of Experimental Botany52 (90001): 381–401. doi:10.1093/jexbot/52.suppl_1.381. PMID 11326045^C.Michael Hogan. 2011. Respiration. Encyclopedia of Earth. Eds. Mark McGinley & C.J.cleveland. National council for Science and the Environment. Washington DC^Ranson S. L.; Thomas M (1960). "Crassulacean acid metabolism". Annual Rev Plant Physiol11 (1): 81–110. doi:10.1146/annurev.pp.11.060160.000501.^ abc Herrera, A. (2008), "Crassulacean acid metabolism and fitness under water deficit stress: if not for carbon gain, what is facultative CAM good for?", Annals of Botany103 (4): 645–653, doi:10.1093/aob/mcn145^ Ting, I P (1985). "Crassulacean Acid Metabolism". Annual Review of Plant Physiology36 (1): 595. doi:10.1146/annurev.pp.36.060185.003115.^ Raven, JA; Edwards, D. (2001). "Roots: evolutionary origins and biogeochemical significance". Journal of Experimental Botany52 (90001): 381–401. doi:10.1093/jexbot/52.suppl_1.381. PMID 11326045
  • C am.ppt

    1. 1. NAME : NIDHI S. DARJI. COURSE : BIOTECHNOLOGY (FY B.sc).COLLEGE : GOVERNMENT SCIENCE COLLEGE.
    2. 2. INTRODUCTION.HISTORICAL BACKGROUND. OVERVIEW OF CAM : A TWO-PART CYCLE. i. DURING THE NIGHT. ii. DURING THE DAY.BENEFITS.COMPARISON WITH C4 METABOLISM.
    3. 3.  Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions.
    4. 4.  In a plant using full CAM, the stoma in the leaves remain shut during the day to reduce evapotranspiration, but open at night to collect carbon dioxide (CO2). The CO2 is stored as the fourcarbonacid malate, and then used during photosynthesis during the day. The pre-collected CO2 is concentrated around the enzyme RuBisCO, increasing photosynthetic efficiency.
    5. 5.  CAM was first suspected by De Saussure in 1804 in his Recherches Chimiques sur la Vegetation, confirmed and refined by Aubert, E. in 1892 in his Recherches physiologiques sur les plantes grasses and expounded upon by Richards, H. M. 1915 in Acidity and Gas Interchange in Cacti, Carnegie Institution.
    6. 6.  The term CAM may have been coined by Ranson and Thomas in 1940, but they were not the first to discover this cycle. It was observed by the botanists Ranson and Thomas, in the Crassulaceae family of succulents (which includes jade plants and Sedum). Its name refers to acid metabolism in Crassulaceae, not the metabolism of crassulacean acid.
    7. 7. CAM is an adaptation for increased efficiencyin the use of water, and so is typically found inplants growing in arid conditions. i. DURING THE NIGHTDuring the night, a plant employing CAM has itsstomata open, allowing CO2 to enter and be fixed asorganic acids that are stored vacuoles in. During theday the stomata are closed (thus preventing waterloss), and the carbon is released to the Calvin cycleso that photosynthesis may take place.
    8. 8. The carbon dioxide is fixed in the cytoplasmof mesophyll cells by a PEP reaction similar tothat of C4 pathway. But, unlike theC4mechanism, the resulting organic acids arestored in vacuoles for later use; that is, theyare not immediately passed on to the Calvincycle. The latter cannot operate during thenight because the light reactions that provideit with ATP and NADPH cannot take place.
    9. 9. i. DURING THE DAYDuring the day, the CO2-storing organic acidsare released from the vacuoles of themesophyll cells and enter the stroma of thechloroplasts where an enzyme releases theCO2, which then enters into the Calvin cycle
    10. 10. CAM photosynthesis- left, at night; right, during the day.1. chloroplast, 2. vacuole, 3. cytoplasm, 4. Calvin cycle, 5.stoma, 6. oxaloacetic acid (OAA), 7. PEP carboxylase(PEPCase), 8. granum (stack of thylakoids), 9. stroma ofchloroplast, 10. malate, 11.malic acid
    11. 11.  The most important benefit of CAM to the plantis the ability to leave most leaf stomata closed duringthe day.  Plants employing CAM are most common in aridenvironments, where water comes at a premium.Being able to keep stomata closed during the hottestand driest part of the day reduces the loss of waterthrough evapotranspiration, allowing such plants togrow in environments that would otherwise be far toodry.
    12. 12.  Plants using only C3 carbon fixation, for example,lose 97% of the water they uptake through the roots totranspiration - a high cost avoided by plants able toemploy CAM.
    13. 13.  The C4 pathway bears resemblance to CAM; bothact to concentrate CO2 around RuBisCO, therebyincreasing its efficiency.  CAM concentrates it in time, providing CO2 duringthe day, and not at night, when respiration is thedominant reaction.  C4 plants, in contrast, concentrate CO2 spatially,with a RuBisCO reaction centre in a "bundle sheathcell" being inundated with CO2.
    14. 14.  Due to the inactivity required by the CAMmechanism, C4 carbon fixation has a greaterefficiency in terms of PGA synthesis.
    15. 15. CAM is named after thePineapple is a CAM plan. family Crassulaceae, to which Jade plant belongs
    16. 16.  C.Michael Hogan. 2011. Respiration. Encyclopedia of Earth. Eds. Mark McGinley & C.J.cleveland. National council for Science and the Environment. Washington DC Ranson S. L.; Thomas M (1960). "Crassulacean acid metabolism". Annual Rev Plant Physiol Herrera, A. (2008), "Crassulacean acid metabolism and fitness under water deficit stress: if not for carbon gain, what is facultative CAM good for?", Annals of Botany 103 Ting, I P (1985). "Crassulacean Acid Metabolism". Annual Review of Plant Physiology 36 Raven, JA; Edwards, D. (2001). "Roots: evolutionary origins and biogeochemical significance". Journal of Experimental Botany 52
    17. 17. THANK YOU

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