Effect of ozone stress on the absorption, distribution, and utilization of nitrogen in rice under different planting densities
2019
Peng, B. | Li, P. | Lai, S. | Wang, Y. | Yang, L. | Wang, Y.
High ozone (O₃) can cause great damage to plants. However, the effect of high O₃ on nitrogen (N) absorption, distribution, and utilization in rice at different growth stages under different planting densities is poorly understood. In the present study, a conventional cultivar (Yangdao 6) and a hybrid cultivar (II You 084) with different planting densities were exposed to an elevated amount of O₃ (E-O₃; 50% higher than that of the control, C-O₃) under a freeair gas concentration enrichment (FACE) system. N absorption, distribution, and utilization of the green leaves, stems, and shoots at tillering, jointing heading, and maturity were investigated. Results showed that E-O₃ significantly increased the N content in the shoots of Yangdao 6 by 7.5%, 12.7%, and 19.6%, respectively, at jointing, heading, and maturity. Also, the N content in the shoots of II You 084 increased by 5.4%, 6.5%, and 8.4% at the corresponding growth stage upon E-O₃ application. E-O₃ significantly decreased N accumulation of II You 084 by 8.3%, 4.9%, 4.7%, and 19.2%, respectively, at tillering, jointing, heading, and maturity. Further, E-O₃ had a decreasing effect on the N distribution in green leaves (p ≤ 0.05) of both cultivars, but exerted an increasing effect on that in the stems of both cultivars (p ≤ 0.05). In addition, E-O₃ significantly decreased the N use efficiency (NUE) for biomass of the two cultivars in all growth stages. These results revealed that E-O₃ could increase the N content in rice plants but decrease the N accumulation and utilization in both cultivars. The effects of E-O₃ on N absorption, distribution, and utilization were not affected by planting density.
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