Many freshwater ecosystems are facing salinity stress, but limited information is available about its effects on submerged macrophytes. Here, we assessed the effects of salinity on sprouting and growth of three submerged macrophytes—Potamogeton crispus, Hydrilla verticillata and Myriophyllum spicatum. We conducted experiments in the lab and the outdoor platform to test for the sprouting and growth responses of selected macrophytes to a gradient of salinity (0.32–10,000 mg Cl⁻ L⁻¹). Sprouting rate, biomass and other related physiological indices were measured in all treatments. We found that lower salinity (100 mg Cl⁻ L⁻¹) increased the turion sprouting rate, and higher salinity (greater than or equal to 5,000 mg Cl⁻ L⁻¹) significantly inhibited the sprouting of P. crispus turions. M. spicatum appeared to have higher tolerance of salinity than H. verticillata. The optimum salinity for the growth of H. verticillata and M. spicatum was 500–1,000 mg Cl⁻L⁻¹ and 100–500 mg Cl⁻ L⁻¹, respectively. Activity of superoxide dismutase (SOD) and production of malondialdehyde (MDA) differed in salinity levels between submerged macrophytes, and higher SOD activity was observed in M. spicatum. This study helped clarify how physiological response mechanisms affecting sprouting and growth of submerged macrophytes are inhibited under high salinity and suggested that SOD plays an important role in the resistance to oxidative stress induced by salinity.

中文翻译：

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盐度对三种沉水植物发芽和生长的影响

许多淡水生态系统都面临盐分胁迫，但是关于其对淹没大型植物的影响的信息有限。在这里，我们评估了盐度对三种淹没大型植物（Potamogeton crispus，Hydrilla verticillata和Myriophyllum spicatum）发芽和生长的影响。我们在实验室和室外平台上进行了实验，以测试所选大型植物对盐度梯度（0.32–10,000 mg Cl ^- L ^-1）的萌芽和生长响应。在所有处理中均测量了发芽率，生物量和其他相关的生理指标。我们发现盐度较低（100 mg Cl ⁻ L ^-1）增加的Turion发芽率，以及更高的盐度（大于或等于5000毫克氯^-大号^-1）显著抑制发芽菹Turion处理器。十字杆菌对盐分的耐受性似乎高于褐线虫。轮叶黄褐藻和十字形分枝杆菌生长的最佳盐度分别为500–1,000 mg Cl ⁻ L ^-1和100–500 mg Cl ⁻ L ^-1。沉水植物之间的盐度水平上超氧化物歧化酶（SOD）的活性和丙二醛（MDA）的产生有所不同，并且在水中的SOD活性更高。M. spicatum。这项研究有助于阐明在高盐度下如何抑制影响淹没大型植物出芽和生长的生理反应机制，并表明SOD在耐盐碱诱导的氧化应激中起重要作用。