Responses of five submerged macrophytes to NaCl salinity in a tropical mesocosm study
Responses of five submerged macrophytes to NaCl salinity in a tropical mesocosm study
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热带中生态系统研究中五种沉水植物对 NaCl 盐度的响应
DOI：
10.1127/fal/2020/1303
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发表时间：
2020-06
影响因子：
1
通讯作者：
Cao Yu
中科院分区：
文献类型：
--
作者：
Chen Tao;Jiang Hong Sheng;Wang Ying;Wang Shaoning;Yin Liyan;Cao Yu
沉水植物是热带淡水生态系统中重要的初级生产者。预计在不久的将来，热带沿海地区强台风等极端气候事件的频率将增加，这可能导致盐度变化，并对水生大型植物产生重大影响。然而，很少有研究集中在盐度对热带沉水植物的影响。在这里，我们进行了为期三个月的热带围隔研究，调查盐度胁迫对五种沉水植物（两个广泛分布的物种Stuckenia pectinata和Myriophyllum spicatum和三个狭窄分布的物种Vallisneria denseserrulata，Ottelia alismoides和Cabomba caroliniana）生长的影响。试验设4个盐度水平处理，即P0（对照，不添加NaCl）、P2（盐度2 ‰）、P5（盐度5 ‰）和PD（动态盐度，初始盐度2 ‰，每月增加0.5 ‰）。我们假设，广泛分布的物种将更好地容忍更高的盐度胁迫相比，在狭窄的范围内分布的物种。一致，bothS。pectinataandM.穗状花序能耐受P5处理，而M. spicatum表现出较小的叶片和减少通气组织面积在叶中脉暴露后。B.密锯齿和O.泽泻在中等盐度下存活，但在生长和繁殖方面对盐度的增加表现出不同的反应。总之，在中国海南岛热带地区，我们发现了不同种的沉水植物对盐胁迫的反应。那些具有更广泛生态位的物种可能会在未来极端盐度变化下表现出更好的生存能力。
Submerged macrophytes are important primary producers in freshwater ecosystems in tropical zones. Extreme climate events such as strong typhoons in tropical coastal areas are expected to increase in frequency in the near future, which could induce salinity changes and significantly influence aquatic macrophytes. However, few studies have focused on the effects of salinity on submerged macrophytes in tropical zones. Here, we conducted a three-month, tropical-zone mesocosm study to investigate the effects of salinity stress on the growth of five submerged macrophytes (two widely distributed speciesStuckenia pectinataandMyriophyllum spicatumand three narrowly distributed speciesVallisneria denseserrulata,Ottelia alismoides, andCabomba caroliniana). Four salinity-level treatments were established, including P0 (control, no addition of NaCl), P2 (salinity of 2 ‰), P5 (salinity of 5 ‰), and PD (dynamic salinity, initial 2 ‰ with monthly salinity increases of 0.5 ‰). We hypothesized that species with broad distribution would better tolerate higher salinity stress compared to species distributed in narrow ranges. Consistently, bothS. pectinataandM. spicatumtolerated P5 treatment, andM. spicatumexhibited smaller leaves and a reduced aerenchyma area in the leaf midrib following exposure. BothV. denseserrulataandO. alismoidessurvived the moderate salinity levels but showed distinct responses to the increase in salinity in regard to growth and reproduction. In conclusion, in tropical Hainan Island, China, we found distinct species-specific responses of the five submerged macrophytes to salinity stress. Those species with broader ecological niches will likely demonstrate better survival under extreme salinity changes in the future.