| 外源Ca2+和K+作用下河口区碱蓬水质净化效果和耐盐碱提高机制 |
| 摘要点击 1146 全文点击 403 投稿时间：2019-06-03 修订日期：2019-07-05 |
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| 中文关键词 碱蓬 盐碱胁迫 河口区 无机离子 小分子有机物 |
| 英文关键词 Suaeda salsa saline-alkali stress estuary areas inorganic ions small organic molecule |
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| 中文摘要 |
| 入海河流中较高的氮、磷污染负荷严重影响近岸海域水质，必须加强陆海统筹.但河口区受海水倒灌影响，水体盐碱浓度高且变化范围大，植物生长困难，去除氮磷能力低，提高植物生存能力是亟需解决的难题.本文通过添加适当浓度的Ca2+和K+，研究提高植物耐盐碱能力以及降低富营养化风险的可能性.结果表明，在pH 8、盐度20‰条件下，外源Ca2+和K+浓度分别为8mmol·L-1和10mmol·L-1的水培实验中，碱蓬对总氮及总磷的去除效率均最高，为对照组的1.53~1.87倍，生长最好，相对生长速率（RGR）为对照组的2.4倍和2.0倍，同浓度Ca2+的缓解作用大于K+.外源Ca2+和K+提高耐盐碱能力的机制体现在碱蓬渗透调节功能的提升：无机渗透调节机制为平衡Na+/K+，提高碱蓬持水能力，叶片与根系中无机离子含量与含水量相关性均在0.966以上；有机渗透调节机制为促进甜菜碱等小分子有机物积累，降低细胞膜脂过氧化作用，Ca2+和K+缓解作用下叶片丙二醛含量最大降幅达72.9%和61.7%.外源Ca2+和K+能够增强碱蓬渗透调节能力，提升耐盐碱能力，促进碱蓬生长，提高碱蓬对氮磷的去除率. |
| 英文摘要 |
| The pollution load of nitrogen and phosphorus in pollutants entering the sea is high, which seriously affects the water quality of coastal water. It is necessary to strengthen land-sea coordination. However, affected by the seawater encroachment, the salt and alkali content of the water in the estuary area is high and the variation range is large, which leads to difficulty in plant growth. The ability of plants to remove nitrogen and phosphorus is reduced. How to improve the survival ability of plants is an urgent problem to be solved. In this study, the addition of appropriate concentrations of Ca2+ and K+ can improve the salinity tolerance of plants and reduce the risk of eutrophication. The results showed that under the condition of pH 8 and salinity 20‰, the removal efficiency of total nitrogen and total phosphorus was the highest in the hydroponic experiment with exogenous Ca2+ and K+ concentrations of 8mmol·L-1 and 10mmol·L-1 respectively, which were 1.53-1.87 times those in the control group. At this time, the growth rate of Suaeda salsa was the best, and the maximum relative growth rates (RGR) were 2.4 times and 2.0 times that of the control group, respectively. The remission effect of Ca2+ was greater than that of K+ at the same concentration. The mechanism by which exogenous Ca2+ and K+improve the salt-alkali tolerance ability of Suaeda salsa was mainly manifested as improving osmotic regulation ability. In the aspect of inorganic osmotic regulation, exogenous ions improved the water-holding capacity of the plant, among which the correlation coefficients of inorganic ion content and water content in leaves and roots were all above 0.966. In terms of organic osmotic regulation, exogenous Ca2+ and K+ all promoted the accumulation of small molecular organic compounds such as betaine in Suaeda salsa, and alleviated plasma membrane peroxidation in leaves. Among them, the largest reductions of malondialdehyde content in leaves were 72.9% and 61.7%, respectively. Therefore, exogenous Ca2+ and K+can enhance the osmotic adjustment ability and promote the growth of Suaeda salsa, thereby improving the removal rate of nitrogen and phosphorus. The results provide a theoretical basis for improving the water purification effect and reducing eutrophication risk in coastal waters. |
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