Abstract Chlorophyll a variable fluorescence and oxygen evolution were measured in microalgae Chlorella and its mutant MS700, which was mutated by nuclear radiation with an increased biomass yield. The mutant MS700 showed an improvement in photosynthetic characteristics under various CO2 concentrations. Results showed that chlorophyll-based flash oxygen yield was 104% higher in MS700 than in the wild type, indicating more available electron acceptors in the plastoquinone pool and a higher light to chemical energy conversion efficiency. The higher chlorophyll a variable fluorescence at the end of PQ pool-regulated phase implied a more robust mechanism for consumption of electrons generated in PSII, indicating a more efficient downstream process. Monitoring of CO2 fixation in the Calvin cycle showed that the mutant had a 27.7% higher capability of incorporating its dissolved inorganic carbon. The oxygen evolution rate was 31.4% higher in MS700, which also indicated a higher CO2 fixation rate. These results consistently demonstrated carbon fixation efficiency in the mutant MS700, resulting in the higher biomass yield.

中文翻译：

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核辐射诱导小球藻突变体MS700光合特性的改善

摘要 在微藻小球藻及其突变体 MS700 中测量了叶绿素 a 可变的荧光和氧气释放量，该突变体通过核辐射发生突变，生物量产量增加。突变体 MS700 在各种 CO2 浓度下显示出光合特性的改善。结果表明，MS700 中基于叶绿素的闪氧产量比野生型高 104%，表明质体醌池中有更多可用的电子受体，光能转化为化学能的效率更高。在 PQ 池调节阶段结束时，较高的叶绿素 a 可变荧光暗示了 PSII 中产生的电子消耗的更强大机制，表明下游过程更有效。卡尔文循环中 CO2 固定的监测表明突变体具有 27。结合溶解的无机碳的能力提高 7%。MS700 的析氧率高出 31.4%，这也表明 CO2 固定率更高。这些结果一致地证明了突变体 MS700 的碳固定效率，从而导致更高的生物质产量。