17α-炔雌醇对三角褐指藻的毒性效应研究

The growth, surface morphology, photosynthetic pigment content, chlorophyll fluorescence parameters, antioxidant system and cell cycle of Phaeodactylum tricornutum in different concentrations of EE2 (0.375, 0.75, 1.5, 3, 6mg/L) were determined. The results show that EE2 could inhibit the growth of Phaeodactylum tricornutum at the 96h-EC₅₀ level of 5.32mg/L, suggesting that EE2 had high toxicity to Phaeodactylum tricornutum. Low concentration of EE2≤0.75mg/L promoted the photosystem II (PSII) activity of Phaeodactylum tricornutum; however, its surface morphology was damaged and its photosynthetic pigment content and maximal photochemical efficiency (F_v/F_m) were significantly reduced under EE2 concentration of 6mg/L. Meanwhile, the light limitation slope (α), the maximum electron transfer efficiency (rETR_max), and semi-saturated light intensity (I_k) also decreased. These results indicate that high concentration of EE2 inhibited the photosystem II (PSII) activity of Phaeodactylum tricornutum. In addition, the activities of both the superoxide dismutase (SOD) and catalase (CAT) and the malondialdehyde (MDA) content significantly increased under the high concentration of EE2, and the cell cycle was arrested in the DNA synthesis phase (S) and division phase (G2/M), demonstrating that a stress response was resulted from the antioxidant system of Phaeodactylum tricornutum.