Abstract：
Microcystis aeruginosa is the main toxic strain in cyanobacterial blooms, and the recruitment stage in its temperature-dependent seasonal succession is considered as the key to its subsequent growth. In this study, a protocol with specific temperature settings was developed as the simulated recruitment stage in order to investigate and confirm the superior inhibitory effects of allelochemicals on M. aeruginosa at that stage of recruitment. One of the most common allelochemicals, gallic acid (GA) (10 mg/L, 20 mg/L) was employed to treat M. aeruginosa under initially low temperature condition (15 °C), then intermediate (20 °C) and last normal (26 °C), which corresponds to the critical temperatures for cyanobacterial recruitment and growth. Growth, metabolism, photosynthetic activity, extracellular polysaccharides (EPS) and microcystins (MCs) release were analyzed and discussed in this study, and a more sustained and better inhibitory effect over a 20-day period was achieved. Notably, GA (10 mg/L) markedly delayed the recruitment of M. aeruginosa from low temperature, with an inhibition efficiency of 85.71 %, and suppressing Fv/Fm and photosynthetic pigments production. It is also observed that M. aeruginosa at recruitment stage exhibited higher sensitivity and poorer resistance to allelochemical treatment, with variable responses suggesting that optimal dosages may alter. The antioxidant enzyme activities remained high under prolonged stress, and the secretion of EPS was stimulated, indicating that cyanobacteria were more inclined to form colonies. While the laboratory-based inhibitory mechanism appeared to increase the release of microcystins in individual cells, the actual concentration of microcystins in natural aquatic environments requires further investigation.
摘要：
铜绿微囊藻是蓝藻水华中的主要毒株,其温度相关的季节性演替中的募集阶段被认为是其随后生长的关键。在这项研究中,为了研究和确认化感物质在招募阶段对铜绿分枝杆菌的优异抑制作用,开发了具有特定温度设置的方案作为模拟招募阶段.最常见的化感物质之一，没食子酸(GA)(10mg/L,20mg/L）用于在初始低温条件（15°C）下处理铜绿假单胞菌，然后中间（20°C）和最后正常（26°C），对应于蓝藻募集和生长的临界温度。增长,新陈代谢，光合活性，胞外多糖（EPS）和微囊藻毒素（MCs）的释放进行了分析和讨论，并且在20天的时间内获得了更持续和更好的抑制作用。值得注意的是,GA(10mg/L)显著延缓了低温下铜绿假单胞菌的募集,抑制效率为85.71%，并抑制Fv/Fm和光合色素的产生。还观察到铜绿假单胞菌在募集阶段对化感处理表现出更高的敏感性和更差的抗性。不同的反应表明最佳剂量可能会改变。抗氧化酶活性在长期胁迫下仍然很高，并刺激了EPS的分泌，表明蓝细菌更倾向于形成菌落。虽然基于实验室的抑制机制似乎增加了单个细胞中微囊藻毒素的释放，微囊藻毒素在自然水生环境中的实际浓度需要进一步研究。
