In the present study, the effects of nitrogen (N) and phosphorus (P) on the growth of Microcystis aeruginosa and the production of microcystins (MCs) were investigated. The results showed that the growth of M. aeruginosa was not merely determined by N or P, but both nutrients were limiting for the species. Moreover, an excess of N and constant P in the culture medium could stimulate the growth of M. aeruginosa , whereas the growth of the species was inhibited in the culture medium containing excess of P and constant N. The optimal growth of M. aeruginosa was at an N:P ratio of 0.1 with the maximal optical density of 1.197 at 680 nm (OD 680 ), whereas the maximal microcystin-LR (MC-LR) content of 228.2 μg·L −1 observed in the culture medium with an N:P ratio of 5. Interestingly, MC-LR production occurred under conditions of N starvation, thereby suggesting that the growth rate of M. aeruginosa was not related to MC-LR production under conditions of nutrient stress.

中文翻译：

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氮磷对铜绿微囊藻生长和微囊藻毒素产量的影响

在本研究中，研究了氮 (N) 和磷 (P) 对铜绿微囊藻生长和微囊藻毒素 (MCs) 产生的影响。结果表明，绿脓杆菌的生长不仅取决于氮或磷，而且这两种营养物质都对该物种具有限制作用。此外，培养基中过量的N和恒定的P可以刺激铜绿假单胞菌的生长，而在含有过量P和恒定N的培养基中，该物种的生长受到抑制。铜绿假单胞菌的最佳生长是N:P 比为 0.1，在 680 nm (OD 680 ) 处最大光密度为 1.197，而在 N 培养基中观察到的最大微囊藻毒素-LR (MC-LR) 含量为 228.2 μg·L -1 :P 比率为 5。有趣的是，MC-LR 的生产发生在 N 饥饿的条件下，