Advantages linked to root development enhance rice biomass accumulation under elevated carbon dioxide conditions
2020
He, Jiang | Zhang, Weiyang | Zhu, Kuanyu | Wang, Zhiqin | Wang, Weilu | Yang, Jianchang
To explore the effects of an increased CO₂ concentration on the growth and N absorption and utilization of different rice (Oryza sativa L.) cultivars, the Liangyoupeijiu (LY) and Nanjing 9108 (NJ) rice cultivars were grown under ambient CO₂ (400 μmol mol⁻¹) and elevated CO₂ (600 μmol mol⁻¹) combined with high N (2.5 mM) and low N (0.5 mM) treatments. The effects of elevated CO₂ on root morphological and physiological characteristics, N uptake and utilization, and dry matter accumulation and distribution were analyzed. The results showed that the elevated CO₂ levels significantly increased the total biomass of LY under different N levels but only significantly increased the total biomass of NJ under high N. Elevated CO₂ significantly increased the N concentrations in the organs of LY but had no significant effect on the N concentrations in the organs of NJ. As a result, elevated CO₂ significantly increased the N accumulation of LY but decreased the N uptake of NJ under low N. Under elevated CO₂ conditions, the total root length and root surface area of LY increased, and the roots also maintained high activity. The larger roots and higher physiological activity and N accumulation of LY were the important reasons for the high levels of dry matter production in response to elevated CO₂. Improvements in the root morphology and physiological activity of rice in future breeding efforts should enhance the dry matter production of low‐response rice.
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