EFFECTS OF IRRADIANCE ON THE INVIVO CO2-O2 SPECIFICITY FACTOR IN TOBACCO USING SIMULTANEOUS GAS-EXCHANGE AND FLUORESCENCE TECHNIQUES
EFFECTS OF IRRADIANCE ON THE INVIVO CO2-O2 SPECIFICITY FACTOR IN TOBACCO USING SIMULTANEOUS GAS-EXCHANGE AND FLUORESCENCE TECHNIQUES
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DOI：
10.1104/pp.94.3.892
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发表时间：
1990-11-01
期刊：
影响因子：
7.4
通讯作者：
PETERSON, RB
中科院分区：
文献类型：
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作者：
PETERSON, RB
研究了气相O2浓度(1%、20.5%和42.0%，v/v)对正常CO2和25~30℃条件下烟草叶片净固定CO2的量子效率和叶绿素荧光效率的影响。当光合作用的光照接近或完全饱和时，在较高的O2水平下，吸收激发的非光化学猝灭明显减少。光化学猝灭只有在饱和光照下才会被高O2浓度所增加。同时测量CO2和H2O交换和荧光产量可以估计净CO2固定和依赖O2的耗散过程之间的线性光合电子传递的分配，例如光呼吸作为叶片内部CO2浓度的函数。研究了活体二氧化碳：O2“特异性因子”(KSP)随辐照度增加的变化。研究发现，Ksp值从中等照度下的85下降到极弱光下的68，在饱和光通量速率下下降到72。根据核酮糖二磷酸羧化酶/加氧酶模型对体内光合作用的适用性进行了讨论。
The effects of gas phase O2concentration (1%, 20.5%, and 42.0%, v/v) on the quantum yield of net CO2fixation and fluorescence yield of chlorophyllaare examined in leaf tissue fromNicotiana tabacumat normal levels of CO2and 25 to 30°C. Detectable decreases in nonphotochemical quenching of absorbed excitation occurred at the higher O2levels relative to 1% O2when irradiance was nearly or fully saturating for photosynthesis. Photochemical quenching was increased by high O2levels only at saturating irradiance. Simultaneous measurements of CO2and H2O exchange and fluorescence yield permit estimation of partitioning of linear photosynthetic electron transport between net CO2fixation and O2-dependent, dissipative processes such as photorespiration as a function of leaf internal CO2concentration. Changes in thein vivoCO2:O2`specificity factor' (Ksp) with increasing irradiance are examined. The magnitudeKspwas found to decline from a value of 85 at moderate irradiance to 68 at very low light, and to 72 at saturating photon flux rates. The results are discussed in terms of the applicability of the ribulose bisphosphate carboxylase/oxygenase enzyme model to photosynthesisin vivo.