摘要:
为探究低pH胁迫对大型藻类早期生长的影响,以铜藻Sargassum horneri为研究对象,设置pH=3.5、4.5、5.5、6.5处理组和自然海水对照组,以不同处理时间分别对铜藻孢子和幼体进行胁迫实验。孢子实验中,于铜藻孢子附着前、后对其进行15、30、60、120 min的酸胁迫,以附着率和脱落率表征低pH对孢子附着的影响;幼体实验中,持续将铜藻幼体暴露于酸性条件下,以脱落死亡率表征pH对幼体的致死效应。结果显示,在短时间酸胁迫下,酸度对铜藻孢子附着的影响显著,附着率随pH值的下降而降低;胁迫时间对孢子的附着影响显著,附着率随胁迫时间的延长而降低,pH值与胁迫时间无交互作用;而当孢子已充分附着后,短期酸胁迫并没有显著影响孢子体的存活。在长时间酸胁迫下,与对照组相比,所有处理组铜藻幼体的存活率均显著降低。研究表明,低pH会对铜藻孢子、幼体的存活生长产生不利影响,并且这种影响在铜藻早期发育的不同阶段有所不同。
关键词:
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低pH
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铜藻
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孢子
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附着
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幼体
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早期发育
Abstract:
The spores and germlings of macroalgae were regarded as the life history stages which are most susceptible to various environmental stresses, including acid stress. Several experiments were conducted to explore the impact of low pH (3.5, 4.5, 5.5 and 6.5 were included) on the early stage of macroalgae, taking the example of Sargassum horneri, involving the spore and germling stages. In the spore experiment, the spores of S. horneri were treated with acidic seawater before and after attachment, respectively. The attachment percent and mortality were calculated to assess the impact of low pH on the spores. In the germling experiment, the germlings of S. horneri were exposed to acid stress constantly and the mortality was calculated to measure the lethal effect of low pH on the germlings. The results indicated that:1) In the short time experiments, the acidity significantly affected the adhesion of spores, while the adhesion ratio decreased with pH value. 2) The adhesion ratio decreased with the exposure time. Exposure time affects the adhesion of spores significantly,with no interaction with pH value. 3) After the spores attaching sufficiently, the survival of spores has a short-term acid stress,which does not significantly affect the survival of spores. Once spore firmly anchored to the substratum, the survival rate of spores was not affected significantly by exposing acid stress. Under longterm acid exposure, significant decreases of the germlings survival in all treatment groups were found compared with the control group. In conclusion, low pH severely affects the survival and growth of S. horneri spores and germlings, and this impact changed depending on the different stages of the early of S. horneri.
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