Figure 1.

Counterintuitive dose-responses of X- or γ-irradiation in the cultivation of C. reinhardtii cells. (A) X-irradiation; (B) γ-irradiation. XR3 (GR3), XR6 (GR6), XR12 (GR12), XR25 (GR25), XR50 (GR50), and XR100 (GR100) represent X-rays (γ-rays) of 3, 6, 12, 25, 50, and 100 Gy, respectively. Mid-exponential phase C. reinhardtii cells were differentially subjected to X- or γ-irradiation to have the absorbed doses of 3, 6, 12, 50, and 100 Gy as described in the Materials and Methods section. The cell densities were compared by measuring the optical density at 750 nm (OD₇₅₀) to evaluate the growth rates of mock and irradiated cells. Data represent the mean ± standard error (SE) with n = 9 from three independent experiments. Different letters indicate significant differences at p < 0.05 (one-way analysis of variance followed by Tukey’s honestly significant difference test).