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Low methane emission in rice cultivars with high radial oxygen loss
- Zheng, Huabin, Fu, Zhiqiang, Zhong, Juan, Long, Wenfei
- Plant and soil 2018 v.431 no.1-2 pp. 119-128
- cultivars, greenhouse gas emissions, methane, oxygen, rice, root tips
- 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.