Optimal regulation mechanisms of leafphotosynthesis and respiration across its longevity

1.菜豆根部补饲蔗糖能增加成熟源叶的碳水化合物含量，加速成熟源叶衰老。这两种情况在年轻的库叶中都不是这样。当菜豆第一叶的环境与植物其他部位的环境不同时，幼叶的光合作用特性不仅受其所处环境的影响，而且还受第一叶环境的影响。这意味着参与了光合作用特性的系统调节。其中一种调控机制与氧化还原调控有关。分析了叶片光合作用特性对生长温度的适应，发现这涉及到从细胞间隙到叶绿体基质的CO2扩散的Rubisco动力学、Rubsoo活化、电子传递活性和内部电导随温度的所有变化。基于碳同位素判别率的测量，分析了C4植物CO2泄漏的浓缩机理。泄漏量(PEPCase固定的每CO2泄漏的比率)随着光照度的降低而增加。这可能与C4在弱光下的表现较差有关。在强光、缺氮和低温胁迫下，负责抗氰呼吸的交替氧化酶表达上调，在抵抗这些胁迫中发挥了重要作用。修订了呼吸成本估算方法，并将其应用于温度对呼吸影响的分析。向日葵叶片背面气孔对光，特别是绿光的敏感性大于正面气孔。对藜属植物叶柄弯曲进行了光生物学分析。至少有三个光传感器显示接合。

1. Sucrose fed to the roots of Phaseolus vulgaris plants caused an increase in the carabohydrate content and accelerated senescence in mature source leaves. Neither of these was the case in young sink leaves.2. When environment of the first leaves of Phaseolus vulgaris plants differed from that for other plant parts, photosynthetic properties of young leaves were affected not only by their environment but also by the environment of the first leaves. This implied involvement of systemic regulation of photosynthetic properties. One of such regulation mechanism was shown to relate to redox regulation.3. Acclimation of leaf photosynthetic properties to the growth temperature was analyzed and found to be involve all the changes in temperature dependences of Rubisco kinetics, Rubisoo activation, electron transport activity, and of internal conductance for CO2 diffusion from the intercellular spaces to chloroplast stroma.4. CO2 leak of the CO2 concentration mechanism of C4 plants was analyzed based on measurement of carbon isotope discrimination. The leakiness (ratio of CO2 leaked per CO2 fixed by PEPCase) increased with the decrease in irradiance. This would relate to the inferior performance of C4 in low light.5. In response to strong light, N deficiency and low temperature, the alternative oxidase which is responsible for the cyanide resistant respiration was upregulated and played important roles in resisting such stresses.6. Methods for respiratory cost evaluations were revised and applied to analyses of temperature effects on respiration.7. Sensitivity of the abaxial stomata to light, in particular green light, was shown to be greater that that of the adaxial stomata in Helianthus annuus leaves.8. Petiole curvature of Chenopodium album was analyzed photobiologically. At least three light sensors were shown to engage.