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探讨O3处理对‘赤霞珠’葡萄叶片光系统功能Ⅱ(PSⅡ)的伤害机制及O3胁迫发生阈值。以一年生‘赤霞珠’为试材,设置不同O3浓度(25、40、55、80和105 n L·L-1),测定叶片叶绿素含量、气体交换和叶绿素荧光参数,分析不同O3浓度处理对葡萄叶片PSII活性的影响。结果表明,随着O3浓度升高,叶片净光合速率(Pn)、气孔导度(Gs)、PSII的实际光化学效率(ΦPSII)、光下最大光化学效率(Fv’/Fm’)、捕获光能用于QA以后的电子传递的概率(ΨEo)、单位面积有活性反应中心的数量(RC/CSm)均呈下降趋势;PSII激发压(1-qP)、K点的相对可变荧光(Wk)、慢相荧光淬灭(qI)呈现上升趋势;在低O3浓度条件下(25~55n L·L-1),Pn的下降主要是由于气孔限制引起的,O3浓度达到并超过80 n L·L-1时,叶绿素含量显著降低,非气孔限制占主导因素,PSII功能开始受到抑制;浓度达到105 n L·L-1时叶片出现较明显的表观伤害症状,电子供体侧伤害程度大于受体侧。实验结果说明,葡萄叶片可以在短时间内(8 h)忍受一定浓度(不超过55 n L·L-1)的O3胁迫,O3浓度达到或超过80 n L·L-1时,PSII功能受到较严重的抑制。
To investigate the damage mechanism of O3 and the threshold of O3 stress on photosystem Ⅱ (PSⅡ) in ’Cabernet Sauvignon’ grape leaves. Taking annual annual ’Cabernet Sauvignon’ as test material, different O3 concentrations (25, 40, 55, 80 and 105 nL·L-1) were set up to measure leaf chlorophyll content, gas exchange and chlorophyll fluorescence parameters, Effect of grape leaf PSII activity. The results showed that the net photosynthetic rate (Pn), stomatal conductance (Gs), PSII actual photochemical efficiency (ΦPSII) and maximum photochemical efficiency (Fv ’/ Fm’ (ΨEo) and the number of active reaction centers per unit area (RC / CSm) showed a decreasing trend; the PSII excitation pressure (1-qP) and K-point relative variable fluorescence (Wk) , The slow phase fluorescence quenching (qI) showed an upward trend. At low O3 concentrations (25-55n L·L-1), the decrease of Pn was mainly due to stomatal limitation, and the O3 concentration reached more than 80 nL · L-1, chlorophyll content decreased significantly, non-stomatal limitation dominated, and PSII function began to be inhibited. At the concentration of 105 n L·L -1, the apparent injury symptoms were obvious and the damage degree of electron donor side was greater than Recipient side. The experimental results showed that grape leaves could tolerate O3 stress at a certain concentration (no more than 55 nL·L-1) in a short time (8 h). When O3 concentration reached or exceeded 80 nL·L-1, PSII function was affected More serious inhibition.