Low methane emission in rice cultivars with high radial oxygen loss
Background and aims
Studies have found significant differences in methane (CH4) emissions among rice cultivars; however, it is unclear whether this difference is related to radial oxygen loss (ROL) from the roots.
Based on a 2-year in situ field study and solution culture experiments on 16 rice cultivars, we investigated CH4 emission levels and their dependence on ROL.
We detected significant differences in CH4 emission and ROL among rice cultivars. The lowest and highest CH4 emission levels were 4.10 and 7.35 g m−2 for early rice, and 14.36 and 23.33 g m−2 for late rice, respectively. The maximum and minimum ROL values were 3.77 and 1.73 mmol plant−1 h−1 for early rice, and 4.18 and 2.08 mmol plant−1 h−1 for late rice, respectively. Seasonal total CH4 emission was negatively correlated with ROL in the early rice season (p < 0.01), and (p < 0.01) in the late rice season. ROL was positively correlated with the number of roots per plant (RN), root tips per plant (RT), and root volume per plant (RV).
We suggest that ROL can be used as a predictive index for CH4 emissions. RN, RT, and RV were the most important factors influencing ROL in rice cultivars.
KeywordsCH4 Cultivar Radial oxygen loss Rice
We thank the anonymous reviewers and editors for their helpful comments and suggestions. This work was supported by the National Natural Science Foundation of China (grant no. 41571293), the National Key Technology R & D Program (grant no. 2013BAD11B02), and the Earmarked Fund for China Agriculture Research System (grant no. CARS-01-26).
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