Mayo W P, Williams T G, Birch D G, Turpin D H
Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6.
Plant Physiol. 1986 Apr;80(4):1038-40. doi: 10.1104/pp.80.4.1038.
Synechococcus leopoliensis was grown over a wide range of dissolved inorganic carbon (DIC) concentrations (4-25,000 micromolar) which were obtained by varying culture pH (6.2-9.6) and the CO(2) concentration of the gas stream (36-50,000 microliters per liter). The [DIC] required to half-saturate photosynthesis (K((1/2)) (DIC)) was found to vary depending upon the ambient DIC concentration at which the cells were grown. Low [DIC] grown cells exhibited low values of K((1/2)) (DIC) (4.7 micromolar) whereas cells grown at high [DIC] exhibited high values of K((1/2)) (DIC) (1-2.5 millimolar). Intermediate concentrations of DIC produced intermediate values. Changes in K((1/2)) (DIC) appeared to be solely a function of [DIC] and were independent of both culture pH and CO(2) concentration. As changes in K((1/2)) (DIC) occur in response to DIC concentrations commonly found in natural systems we suggest this adaptation may be of ecological significance.
利奥波利斯聚球藻在很宽的溶解无机碳（DIC）浓度范围（4 - 25000微摩尔）内生长，这些浓度通过改变培养pH值（6.2 - 9.6）和气流中的CO₂浓度（每升36 - 50000微升）来获得。发现使光合作用半饱和所需的[DIC]（K₁/₂(DIC)）会因细胞生长时的环境DIC浓度而异。在低[DIC]条件下生长的细胞表现出较低的K₁/₂(DIC)值（4.7微摩尔），而在高[DIC]条件下生长的细胞表现出较高的K₁/₂(DIC)值（1 - 2.5毫摩尔）。中等浓度的DIC产生中间值。K₁/₂(DIC)的变化似乎仅取决于[DIC]，且与培养pH值和CO₂浓度均无关。由于K₁/₂(DIC)的变化是对自然系统中常见的DIC浓度做出的响应，我们认为这种适应性可能具有生态意义。
