Effects of growth and measurement light intensities on temperature dependence of CO(2) assimilation rate in tobacco leaves.
Effects of growth and measurement light intensities on temperature dependence of CO(2) assimilation rate in tobacco leaves.
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DOI：
10.1111/j.1365-3040.2009.02067.x
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发表时间：
2010-03
期刊：
影响因子：
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通讯作者：
W. Yamori;J. R. Evans;S. von Caemmerer
中科院分区：
文献类型：
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作者：
W. Yamori;J. R. Evans;S. von Caemmerer
由于生长光强改变了光合作用组分之间的氮素分配，因此研究了生长光强对烟草CO2同化速率温度依赖性的影响。叶片氮素、核酮糖1，5-二磷酸羧基/加氧酶(Rubisco)和细胞色素f(Cytf)含量随生长光强的增加而增加，但Cytf/Rubisco比值变化不大。用碳同位素判别法测定的叶肉对CO2扩散的电导g(M)随生长光强的增加而增加，但不随测量光强的增加而增加。利用不同光强和温度下CO2同化速率对叶绿体CO2浓度(C(C))的响应来估算Rubisco的最大羧化速率(V(CMAX))和叶绿体电子传递速率(J)。在任何给定温度下，最大电子传递速率与细胞色素f含量呈线性关系(例如，在25℃和40℃时，细胞色素f分别为115和179微摩尔电子摩尔·摩尔·摩尔·S(-1))。从RuBP羧化向RuBP再生极限转变的叶绿体CO(2)浓度(C(Tras))随叶温升高而增大，与生长光强无关，与细胞色素f/Rubisco的比值恒定一致。在烟草中，在380微摩尔摩尔(-1)CO(2)浓度和强光下，CO2的同化速率受到32℃以上RuBP羧化和32℃以下RuBP再生的限制。
Effects of growth light intensity on the temperature dependence of CO(2) assimilation rate were studied in tobacco (Nicotiana tabacum) because growth light intensity alters nitrogen allocation between photosynthetic components. Leaf nitrogen, ribulose 1.5-bisphosphate carboxylase/oxygenase (Rubisco) and cytochrome f (cyt f) contents increased with increasing growth light intensity, but the cyt f/Rubisco ratio was unaltered. Mesophyll conductance to CO(2) diffusion (g(m)) measured with carbon isotope discrimination increased with growth light intensity but not with measuring light intensity. The responses of CO(2) assimilation rate to chloroplast CO(2) concentration (C(c)) at different light intensities and temperatures were used to estimate the maximum carboxylation rate of Rubisco (V(cmax)) and the chloroplast electron transport rate (J). Maximum electron transport rates were linearly related to cyt f content at any given temperature (e.g. 115 and 179 micromol electrons mol(-1) cyt f s(-1) at 25 and 40 degrees C, respectively). The chloroplast CO(2) concentration (C(trans)) at which the transition from RuBP carboxylation to RuBP regeneration limitation occurred increased with leaf temperature and was independent of growth light intensity, consistent with the constant ratio of cyt f/Rubisco. In tobacco, CO(2) assimilation rate at 380 micromol mol(-1) CO(2) concentration and high light was limited by RuBP carboxylation above 32 degrees C and by RuBP regeneration below 32 degrees C.