Oxygen exchange in relation to carbon assimilation in water-stressed leaves during photosynthesis
Oxygen exchange in relation to carbon assimilation in water-stressed leaves during photosynthesis
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DOI：
10.1093/aob/mcf023
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发表时间：
2002-06-01
期刊：
影响因子：
4.2
通讯作者：
Fock, HP
中科院分区：
文献类型：
--
作者：
Haupt-Herting, S;Fock, HP
为了研究水分胁迫下番茄光合电子的代谢消耗和多余光能的耗散，利用O-18(2)和(CO2)-C-13质谱法测定了番茄植株O-2和CO2气体交换。在水分胁迫下，总O-2演化（E-o）、总O-2吸收量（U-o）、净CO2吸收量（P-N）、总CO2吸收量（TPS）和总CO2演化（E-C）呈下降趋势。应力作用下P-N/E-o比值下降，U-o/E-o和E-c/TPS比值上升。线粒体在光照下的呼吸，可以直接通过(CO2)-C-13在3000 μ l(-1) (CO2)-C-13吸收过程中的(CO2)-C-12进化来测量，相对于总CO2进化和乙醇酸途径的CO2释放来说是很小的。由此可见，水分胁迫降低了PSII、卡尔文循环和线粒体呼吸。计算了CO2同化、光呼吸和梅勒反应所消耗的光合电子的百分比：在对照叶片中，超过50%的电子被CO2同化消耗，23%被光呼吸消耗，13%被梅勒反应消耗。在严重胁迫下，被CO2同化和梅勒反应耗散的电子百分比下降，而用于光呼吸的电子百分比增加了一倍。光呼吸过程中电子的消耗可以减少水分亏缺时损伤的可能性。(C) 2002年植物学年鉴。
In a study on metabolic consumption of photosynthetic electrons and dissipation of excess light energy under water stress, O-2 and CO2 gas exchange was measured by mass spectrometry in tomato plants using O-18(2) and (CO2)-C-13. Under water stress, gross O-2 evolution (E-o), gross O-2 uptake (U-o), net CO2 uptake (P-N), gross CO2 uptake (TPS), and gross CO2 evolution (E-C) declined. The ratio P-N/E-o fell during stress, while the ratios U-o/E-o and E-c/TPS rose. Mitochondrial respiration in the light, which can be measured directly by (CO2)-C-12 evolution during (CO2)-C-13 uptake at 3000 mul l(-1) (CO2)-C-13, is small in relation to gross CO2 evolution and CO2 release from the glycolate pathway. It is concluded that PSII, the Calvin cycle and mitochondrial respiration are down-regulated under water stress. The percentages of photosynthetic electrons dissipated by CO2 assimilation, photorespiration and the Mehler reaction were calculated: in control leaves more than 50 % of the electrons were consumed in CO2 assimilation, 23 % in photorespiration and 13 % in the Mehler reaction. Under severe stress the percentages of electrons dissipated by CO2 assimilation and the Mehler reaction declined while the percentage of electrons used in photorespiration doubled. The consumption of electrons in photorespiration may reduce the likelihood of damage during water deficit. (C) 2002 Annals of Botany Company.