PHOTOSYNTHESIS AND RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE OXYGENASE IN RICE LEAVES FROM EMERGENCE THROUGH SENESCENCE - QUANTITATIVE-ANALYSIS BY CARBOXYLATION OXYGENATION AND REGENERATION OF RIBULOSE 1,5-BISPHOSPHATE
PHOTOSYNTHESIS AND RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE OXYGENASE IN RICE LEAVES FROM EMERGENCE THROUGH SENESCENCE - QUANTITATIVE-ANALYSIS BY CARBOXYLATION OXYGENATION AND REGENERATION OF RIBULOSE 1,5-BISPHOSPHATE
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DOI：
10.1007/bf00401181
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发表时间：
1985-01-01
期刊：
影响因子：
4.3
通讯作者：
OHIRA, K
中科院分区：
文献类型：
--
作者：
MAKINO, A;MAE, T;OHIRA, K
水稻叶片寿命过程中气体交换速率的变化通过测量核酮糖1，5-二磷酸(RuBP)在2000(饱和)和500(亚饱和)量子点的光子注量率下的羧化/氧化和再生的变化进行了定量分析。M2.cntdo.环境空气条件下的S1。RuBP的水平总是高于RuBP羧基酶的活性部位浓度(EC 4.1.1.139)，与所提供的辐射无关。CO2同化速率与胞间CO2浓度的关系分析表明，RuBP再生并不限制CO2的同化。体内估计的RuBP羧基酶/加氧酶活性与每个光照水平下的二氧化碳同化速率呈线性相关。这种酶的活性恰好足以解释饱和光照下的CO2同化速率，比亚饱和光照下的CO2同化速率高出35%。分析了在亚饱和光照下的同化率与胞间二氧化碳浓度的函数关系，结果表明，酶的激活起到了限制作用。结果表明，在环境空气条件下，水稻叶片的CO2同化速率受RuBP羧化/氧化能力的限制。
Changes in gas-exchange rates during the life span of the leaves of rice (Oryza sativa L.) were analyzed quantitatively by measuring changes in the carboxylation/oxygenation and regeneration of ribulose 1,5-bisphosphate (RuBP) at photon fluence rates of 2000 (saturating) and 500 (subsaturating) .mu.mol quanta .cntdot. m2 .cntdot. s1 under ambient air conditions. The RuBP levels were always higher than the active-site concentrations of RuBP carboxylase (EC 4.1.1.139), irrespective of the irradiance supplied. Analysis of the CO2-assimilation rate as a function of intercellular CO2 concentration indicated that RuBP regeneration does not limit CO2 assimilation. The estimated RuBP-carboxylase/oxygenase activity in vivo was linearly correlated to the rate of CO2 assimilation at each level of irradiance. This enzyme activity was just enough to account for the rate of CO2 assimilation at the saturating irradiance and was 35% more than the rate of CO2 assimilation at the subsaturating irradiance. Analysis of the assimilation rate at subsaturating irradiance as a function of intercellular CO2 concentration indicated that a limitation caused by enzyme activation comes into play. The results indicate that the rate of CO2 assimilation in rice leaves under ambient air conditions is limited during their entire life span by the RuBP-carboxylation/oxygenation capacity.