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由于无CO_2空气中,光合CO_2固定受阻,光合环中间产物无法正常再生,以往有关无CO_2空气中C_3植物叶片CO_2猝发研究报道都是测定预光合处理的叶片迅速移入无CO_2空气中,断光后瞬间的CO_2猝发,且仅作为光呼吸强度的测定指标。在探讨无CO_2空气中C_3植物叶片光合碳代谢与光抑制相互关系时,作者观察到经光合预处理的小麦、水稻叶片,在无CO_2空气中随光暗交替,CO_2猝发可长时间进行。其强度及持续时间受氧气浓度、光强及光合产物积累量的显著影响,并受到光合能量代谢抑制剂DCMU的显著抑制。暗呼吸抑制剂碘乙酸等无明显影响。饥饿(暗处理)叶片在无CO_2空气中,CO_2猝发活性需经一定时间的光诱导方可表现。诱导过程与气孔导度变化不完全相关。诱导所需时间与光强成反比,与饥饿程度成正比。叶片光合CO_2固定以及高于2％的氧气浓度非诱导过程所必需。上述结果清楚表明:无CO_2空气中,C_3植物叶片CO_2猝发其碳源不仅来源于Calvin循环中活跃的中间产物,而且还可能经某种转化途径来源于贮藏性光合产物。本研究结果不仅揭示了无CO_2空气中C_3植物光合碳代谢的复杂性,其重要意义还在于揭示了在无CO_2空气中,甚至在相当长一段时间内,C_3植物光合碳循环并非停止,而是维持某种特殊运转。其作用可能在于通过重新动员贮藏性光合产物,“回迁”光合碳循环,参与光合机构对光抑制的适应。
In the absence of CO 2, photosynthesis CO 2 was blocked and the photosynthetic ring intermediates could not be regenerated normally. Previous studies on the CO 2 burst in leaves of C 3 plants without CO 2 have reported that the pre-photosynthesis leaves were rapidly moved into CO 2 -free air, Instantaneous CO 2 burst, and only as a measure of photorespiratory intensity. When discussing the relationship between photosynthetic carbon metabolism and photoinhibition of C_3 plants in CO2-free air, the authors observed that photosynthetic pretreatment of wheat and rice leaves alternated with light and dark in the absence of CO_2 air, and CO 2 burst could be carried out for a long time. Its intensity and duration were significantly affected by oxygen concentration, light intensity and photosynthetic product accumulation, and significantly inhibited by DCMU, a photosynthetic energy metabolism inhibitor. Dark respiratory depression iodine acetic acid and other no significant effect. Starvation (dark treatment) leaves in CO 2 -free air, CO 2 burst activity to be light-induced only after a certain period of time. Induction and stomatal conductance changes are not completely related. Induction time and light intensity is inversely proportional to the degree of hunger is proportional to. Leaf photosynthesis CO 2 fixation and oxygen concentration above 2% are necessary for the non-induction process. The above results clearly show that the CO 2 bursts in C 3 plants not only originate from the active intermediate in the Calvin cycle, but also may be derived from the storage photosynthetic products via some transformation pathway. The results of this study not only reveal the complexity of photosynthetic carbon metabolism of C_3 plants in CO_2-free air, but also reveal the importance of C_3 photosynthetic carbon cycling in CO_2-free air even for a long period of time Maintain a special operation. Its possible role is to participate in photosynthetic apparatus adaptation to photoinhibition by “re-mobilizing” the photosynthetic carbon cycle by re-mobilizing stored photosynthetic products.