CO2 fixation adjustment mechanism explained by the chemical energy production and consumption balance in photosynthesis

本实验研究的目的是从光合作用产生和消耗的化学能的库源平衡的角度，以CO2交换速率为基础，了解光化学系统和CO2固定系统之间的相互调节机制，为提高叶片光合作用的能量利用效率提供基础知识。通过本研究，作者以甘薯(Ipomoea Batatas)和绿豆(Vigna Radiata)的叶片为材料，开发了新的实验技术，并应用所开发的方法获得了一些有趣的结果。利用本文设计的表皮剥离技术，可以在同化室中用没有表皮或气孔阻力的叶片来测量叶肉细胞的CO2交换速率，并根据测量结果估计体内主要光合酶(RuBPCase/Oase)的活性和激活状态。此外，为了通过间歇照明改变叶片中的化学能量状态，还设计并改进了高速旋转扇区。对间歇光照的光合作用响应的认识可以成为理解光合作用中基于化学能的汇-源平衡的相互调节机制的线索。今后进一步深入研究，有望对光合作用的调节机制作出更有特色、更正确的解释，建立提高光合作用利用效率的生理遗传学理论和方法。

The aim of this experimental research is to understand, based on the CO2 exchange rate, the mutual adjustment mechanism between photochemical system and CO2 fixation system from the viewpoint of the sink-source balance in chemical energy produced and consumed for photosynthesis, and to obtain fundamental knowledge for increasing the energy utilization efficiency in leaf photosynthesis. Through this study, using leaves of sweet potato (Ipomoea batatas) and mungbean (Vigna radiata), the author has developed new experimental techniques and obtained some interesting results by applying the developed methods. By using the epidermis peeling technique devised here, CO2 exchange rate of the mesophyll can be measured with an assimilation chamber using a leaf without epidermis or stomatal resistance, and from the measurements, the in vivo activity and activation status of the main photosynthetic enzyme (RuBPCase/Oase) are estimated. Also to change chemical energy status in a leaf by intermittent illuminations, the rotating sector of high speed has been devised and improved. Knowledge of the photosynthetic response to intermittent illuminations can become a clue to understand the mutual adjustment mechanism in photosynthesis based on the sink-source balabce of chemical energy. Further detailed study to be made from now on may promise to give more distinctive and correct explanation on the adjustment mechanism for photosynthesis and establish physiological and genetical theory and method to increase the photosynthetic utilization efficiency.