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| Differential effects of ozone pollution on photosynthesis and growth of rice during two growth stages |
| Received:February 01, 2021 |
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| KeyWord:ozone;rice;photosynthetic characteristics;different growing stages |
| Author Name | Affiliation | E-mail | | FU Rao | Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China | | | SHANG Bo | Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China | | | ZHANG Guoyou | Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China | | | FENG Zhaozhong | Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China | zhaozhong.feng@nuist.edu.cn |
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| Abstract: |
| Numerous studies have explored the adverse effects of ozone(O3) on rice growth, but it is unclear whether O3 has the same effect during different growth stages of rice. This study was conducted in open top chambers, using two O3 treatments(CF:charcoal-filtered air; NF40:ambient air+40 nmol·mol-1 O3). The O3 fumigation treatments were conducted using two rice cultivars(Hybrid rice Shanyou 63 and Japonica rice Wuyujing 3) at two growth stages(tiller and jointing stage, and heading and grain filling stage). A total of three experimental treatments were conducted:The entire growth period of rice under the CF treatment(CF); O3 fumigation at the tiller and jointing stage with the other growth stage under the CF treatment(O3-1), O3 fumigation at the heading and grain filling stage with the other growth stage under the CF treatment(O3-2). The AOT40(accumulative value of hourly O3 concentration over 40 nmol·mol-1 during the experiment) of the O3-1 and O3-2 treatments were(9.54 ±0.41)μmol·mol-1·h and(9.61 ±0.23)μmol·mol-1·h, respectively. By measuring the growth and photosynthetic variables, the effects of O3 were explored during the two growth stages. The results showed that relative to the CF treatment, the O3-2 treatment produced a significantly reduced average maximum carboxylation rate(Vcmax) and excitation energy capture efficiency in the PSⅡ reaction center(F' v/F' m) by 43.2% and 10.8% across the two cultivars, respectively. The saturated photosynthetic rate(Asat), stomatal conductance(Gs), and maximum electron transfer rate(Jmax) decreased by 44.3%, 55.2%, and 51.8% in cultivar Shanyou 63, respectively, and quantum yield of PS Ⅱ in the light(PhiPS2) decreased by 25.8% in cultivar Wuyujing 3. There were no significant differences in leaf mass per area, chlorophyll content, or leaf nitrogen content under the different O3 treatments. No significant interaction between different O3 treatments and cultivars occurred for any of the variables. Thus, the effect of O3 on rice was greater during the heading and filling stage, and the effect of O3 on the two rice cultivars was similar. |
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