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利用田间原位开顶式熏气装置(Open-Top Chambers,OTCs),研究了5种不同浓度臭氧(O3)处理下(自然大气处理,AA;箱内大气处理,NF;箱内低浓度O3处理,NF+30nL·L-1;箱内中等浓度O3处理,NF+60nL·L-1;箱内高浓度O3处理,NF+90nL·L-1)我国珠三角地区水稻产量损失与累积气孔O3通量(AFstX)和累积O3浓度(AOT40和SUM06)的关系,同时利用边界线拟合法,分析了不同环境因子作用下水稻剑叶气孔导度的变化特征。结果表明:水稻气孔运动的光饱和点和最适温度分别约为500μmol·m-2·s-1和33.1℃,水汽压差、物候期和O3暴露剂量的气孔限制临界值分别约为1.3kPa、500℃·d和5μL·L-1·h,高于此临界值时,气孔导度会明显下降。利用Jarvis气孔导度模型对水稻剑叶气孔导度和气孔O3吸收通量进行了预测,结果表明Jarvis模型解释了水稻实测气孔导度61%的变异性。O3吸收速率临界值(X)为2nmol·m-2·s-1时,累积气孔O3吸收量(AFst2)与水稻产量的相关性最高(R2=0.63),明显高于O3浓度指标(AOT40和SUM06)与水稻产量的相关性(R2值分别为0.49和0.51),表明基于气孔通量的O3风险评价指标能更好地反映水稻产量的变化。
Five open-top Chambers (OTCs) were used to study the effects of five different concentrations of O3 (natural atmosphere treatment, AA treatment, NF, low concentration O3 Treatment with NF + 30nL·L-1, medium-level O3 treatment, NF + 60nL·L-1, high concentration O3 treatment and NF + 90nL·L-1), yield loss and accumulation of stomata in the Pearl River Delta O3 fluxes (AFstX) and cumulative O3 concentrations (AOT40 and SUM06) were analyzed. The changes of stomatal conductance of rice leaves under different environmental factors were analyzed by the boundary line fitting method. The results showed that the stomatal limitation threshold and stomatal limitation of rice stomatal movement were about 500μmol · m-2 · s-1 and 33.1 ℃, and the stomatal limitation threshold of water vapor pressure difference, phenological period and O3 exposure dose were about 1.3kPa , 500 ℃ · d and 5μL · L-1 · h, above which the stomatal conductance decreased significantly. Stomatal conductance model of Jarvis was used to predict stomatal conductance and stomatal O3 flux in rice plants. The results showed that the Jarvis model explained the variability of 61% of the measured stomatal conductance in rice. The correlation between accumulation of stomatal O3 (R2 = 0.63) and accumulation of stomatal O3 (O3) was significantly higher than that of O3 (AOT40 and AOT40) when O3 absorption rate was 2nmol · m-2 · s-1 SUM06) and rice yield (R2 values were 0.49 and 0.51, respectively), indicating that the O3 risk assessment based on stomatal flux could better reflect the change of rice yield.