Among the strategies for treating harmful algal blooms, flocculation using modified clay (MC) has been widely applied in the field. This paper studied the mitigation of MC on Amphidinium carterae Hulburt, finding that MC could not only effectively remove A. carterae, but also affect the physiological activities of the residual algae and inhibit their normal growth. The superoxide dismutase (SOD) activity, catalase (CAT) activity and malondialdehyde (MDA) content of the residual algae significantly increased compared with the control, indicating that MC stimulated the accumulation of reactive oxygen species (ROS) in algal cells. In addition, the cell density was significantly correlated with the SOD activity, CAT activity and MDA content in the experiment groups, suggesting that intracellular ROS might be the main internal factor inhibiting cell growth. To reveal the mechanism of ROS generation, this paper further evaluated the effect of MC on photosynthesis in the residual microalgae, and found that compared with the control the absorption flux per photosystem II (PSII) reaction center (ABS/RC), the trapping flux per RC (TR₀/RC) and the electron transport flux per RC (ET₀/RC) increased, while the TR₀/ABS and ET₀/ABS decreased after adding 0.10 g/L and 0.25 g/L MC. These findings indicate that the MC led to an imbalance between photosynthetic light absorption and energy utilization and that the partial RCs became non-primary quinone electron acceptor (Q_A)-RCs, further inducing the over-excitation of the active RCs. And MC caused the suppression of the electron transport chain (ETC): the ETC from the Q_A to the secondary quinone electron acceptor (Q_B) was blocked and the size of plastoquinone pool decreased, which could induce the over-reduction of PSII. The over-excitation of PSII and the damaged ETC likely induce the generation of ROS during photosynthesis. Thus, MC likely induced the accumulation of intracellular ROS due to photosynthesis inhibition, consequently hindering the growth of the residual algae.

在处理有害藻华的策略中，使用改性粘土（MC）的絮凝已广泛应用于该领域。本文研究了缓蚀炭疽菌Hulburt对MC的缓解作用，发现MC不仅可以有效去除炭疽杆菌，还会影响残留藻类的生理活性并抑制其正常生长。与对照组相比，残留藻类的超氧化物歧化酶（SOD）活性，过氧化氢酶（CAT）活性和丙二醛（MDA）含量显着增加，表明MC刺激了藻类细胞中活性氧（ROS）的积累。此外，在实验组中，细胞密度与SOD活性，CAT活性和MDA含量显着相关，表明细胞内ROS可能是抑制细胞生长的主要内在因素。为了揭示ROS的产生机理，本文进一步评估了MC对残留微藻光合作用的影响，发现与对照相比，每个光系统II（PSII）反应中心（ABS / RC）的吸收通量，₀ / RC）和每RC的电子传输通量（ET ₀ / RC）增加，而TR ₀ / ABS和ET ₀ / ABS在添加0.10 g / L和0.25 g / L MC后降低。这些发现表明，MC导致光合光吸收和能量利用之间的不平衡，部分RC变成了非伯醌电子受体（Q _A）-RC，进一步引起了活性RC的过度激发。MC抑制了电子传输链（ETC）：从Q _A到次级醌电子受体（Q _B的ETC）被阻滞，质体醌库的大小减小，这可能导致PSII的过度减少。PSII的过度激发和受损的ETC可能会在光合作用期间诱导ROS的生成。因此，MC可能由于光合作用的抑制而诱导了细胞内ROS的积累，从而阻碍了残留藻类的生长。