Phytoremediation of Nitrous Oxide: Expression of Nitrous Oxide Reductase from Pseudomonas Stutzeri in Transgenic Plants and Activity thereof

ii Acknowledgements iv Table of Content v List of Abbreviations ix List of Figures xi List of Tables xiii Chapter 1 1 General Introduction 1.1 Greenhouse gases and climate change 1 1.1.1 Global warming and climate change 1 1.1.2 Greenhouse gases 2 1.1.3 Rate of change 3 1.1.4 Agriculture’s impact on greenhouse gas emissions 3 1.2 The nitrogen cycle 4 1.2.1 Current status of nitrogen in the environment 4 1.2.2 Nitrifying and denitrifying cycles 5 1.2.3 Strategies to mitigate nitrogen emissions 8 1.3 Nitrous oxide 9 1.3.1 The properties of nitrous oxide 9 1.3.2 The effects of nitrous oxide 10 1.3.3 Agriculture and nitrous oxide emissions 11 1.4 Nitrous oxide reductase 12 1.4.1 The structure of nitrous oxide reductase 13 1.4.2 The nos genes and their products 17 1.4.3 NosZ biogenesis 21 1.5 Phytoremediation 23 1.5.1 Phytoremediation technologies 23 1.5.2 Phytoremediation strategies and their uses 24 1.5.3 Phytoremediation: advantages, limitations, present status 29 1.6 Hypothesis and Objective 32