Effectiveness of plant growth regulators on emission reduction of greenhouse gas (Nitrous oxide): An approach for cleaner environment

Global climate change is one of the most prominent and complex environmental problems caused by increasing concentrations of atmospheric greenhouse gases. Rice paddies are an important anthropogenic source of nitrous oxide (N2O), a greenhouse gas approximately 298 times stronger than carbon dioxide. Identifying a suitable mitigation method for N2O emissions from rice agriculture, while maintaining optimum crop productivity is strongly needed. A 2-year field study was conducted on rice to assess N2O emissions in response to the application of different plant growth regulators (PGRs). The PGRs abscisic acid (ABA) and cytozyme (20 mg L−1), kinetin (10 and 20 mg L−1) and wet tea extract (1:20 w/w) along with distilled water as control were sprayed at the tillering and panicle initiation stages of rice. Compared with control treatment, exogenously applied ABA and kinetin (10 and 20 mg L−1) significantly (p < 0.01) reduced N2O emission primarily through regulation of leaf growth, stomatal frequency, and xylem vessel size of rice plants. Cytozyme and kinetin improved the grain yield through efficient photosynthesis. Leaf area index, tiller number, leaf photosynthesis, and transpiration were found to be directly associated (p < 0.05) with N2O emission. The PGRs regulated N2O transport by manipulating anatomical and physiological processes. Kinetin (10 mg L−1) application can be suitable for N2O emission reduction coupled with an increase in economic productivity. Considering the effect of N2O on global climate change, such mitigation measures may be effective for sustaining a cleaner environment for global community.