Review

Strategies to lower greenhouse gas level by rice agriculture

Ya-Wen Hsu¹, Shashi Kant Singh¹, Ming-Yung Chiang², Yi-Yen Wu² and Ing-Feng Chang^1,3*

¹Institute of Plant Biology, National Taiwan University, Taipei, Taiwan.

²Green Power Agriculture CO., LTD. Taichung, Taiwan.

³Department of Life Science, National Taiwan University, Taipei, Taiwan.

*Corresponding author. E-mail: ifchang@ntu.edu.tw. Tel: 02-33662534. Fax: 02-23918940.

Accepted 19 December, 2008

The Earth's average temperature has risen to about 1^oF in the past 100 years and is projected to rise another 3 to 10^oF in the next 100 years. Human activity in last few decades has increased the concentration of various greenhouse gases, leading to increased CO₂, methane, tropospheric ozone, CFCs and nitrous oxide. To normalize the nature health many researchers around globe devote their life to searching a good way to reduce greenhouse gases, therefore global warming has been taken a full flag attention worldwide. In this minireview we introduced different agriculture strategies used so far to reduce greenhouse gases. The concept principally focuses on transgenic plants and integrated management system. The transgenic rice (basically a C3 plant) harboring C4 photosynthetic genes phosphoenolpyruvate carboxylase (PEP) carboxylase (PEPC) and pyruvate orthophosphate dikinase (PPDK) has been showed to increased photosynthetic capacity and efficiency of carbon dioxide assimilation. However, many drawbacks that is, field test, stability of the transgenic lines are unavoidable. Taiwan farmers utilized commercial hormone and fertilizer combination to rice growing. Very recently the integrated management system is set up based on plant physiological needs. It did increase the rice yield per growing unit area and grain bearing rate. The fixation of CO₂ to carbon was therefore expected to be greater, which indirectly reduced the amount of CO₂ in the field. On the other hand, the emission of methane may also be reduced with better CO₂ assimilation and the less carbon delivered to the ground. This strategy can both increase the rice yield and have benefits on global warming mitigation. In short-term, the integrated management system, an eco-farming approach, would be a better solution than transgenic plants.

Key words: Greenhouse gas, rice, C4 plant, PEP carboxylase, pyruvate orthophosphate dikinase.