This study examined effects of mangrove plants Kandelia obovata and Aegiceras corniculatum on harmful algal species. While A. corniculatum leaf extract had no inhibitory effect, K. obovata leaf extract significantly inhibited the growth of two harmful algal species Alexandrium tamarense and Karenia mikimotoi. The inhibitory effect was concentration-dependent, with over 90 % inhibition at the highest concentration. Morphological changes and cell size reduction were observed in both microalgae. Excessive production of reactive oxygen species and damage to algal photosynthetic system were found. The allelopathic effect of K. obovata on K. mikimotoi with low-concentration repeated exposure was more effective than high-concentration single exposure. The EC50 of K. obovata (0.33 g L−1) was lower than reported values on other coastal plants. Higher inhibitory effects of K. obovata were found on naked algal species than the armoured ones. These findings suggest potential applications of K. obovata leaf extract in controlling harmful algal blooms.

中文翻译：

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红树林植物秋茄和桐花树对有害藻类的差异化感作用：在藻类水华控制中的潜在应用


这项研究研究了红树林植物秋茄和桐花树对有害藻类的影响。虽然羊角藻叶提取物没有抑制作用，但 K. obovata 叶提取物却显着抑制两种有害藻类塔玛亚历山大藻和米基本凯伦藻的生长。抑制作用呈浓度依赖性，最高浓度时抑制率超过90%。在两种微藻中均观察到形态变化和细胞尺寸减小。发现活性氧产生过量并对藻类光合作用系统造成损害。低浓度重复接触K. obovata对御木本K. mikimotoi的化感作用比高浓度单次接触更有效。 K. obovata (0.33 g L−1) 的 EC50 低于其他沿海植物的报告值。研究发现，K. obovata 对裸藻的抑制作用高于铠装藻。这些发现表明 K. obovata 叶提取物在控制有害藻华方面的潜在应用。