【摘要】：近年來，有害藻華在我國沿海頻繁暴發(fā)，對近岸生態(tài)環(huán)境和人類健康構(gòu)成了極大威脅。而有害藻華的頻發(fā)與環(huán)境條件及富營養(yǎng)化密切關(guān)聯(lián)，成為國內(nèi)外研究者關(guān)注的焦點(diǎn)。紅色赤潮藻（Akashiwo sanguinea）是廣受關(guān)注的有害藻華原因種之一，研究者對該藻株藻華期間的水文氣象、生物、化學(xué)等因子進(jìn)行了大量研究，但對該藻種群增長研究較少，其藻華的生消機(jī)制仍不清楚。因此，弄清紅色赤潮藻種群增長及其孢囊形成機(jī)制對于揭示該物種引發(fā)藻華的消亡及其防治具有重要意義。 本文以我國煙臺四十里灣海域典型藻華肇事種紅色赤潮藻為研究對象，采用一次性培養(yǎng)的方法，研究主要環(huán)境因子和氮營養(yǎng)鹽形態(tài)對其種群增長的影響，并初步研究了氮營養(yǎng)鹽脅迫對其孢囊形成的影響機(jī)制，，結(jié)果發(fā)現(xiàn)： （1）紅色赤潮藻對溫度、鹽度、光照具有較寬的適應(yīng)范圍，其最適生長溫度范圍為20~25℃，鹽度為20，光照強(qiáng)度為4000lx；但當(dāng)溫度低至15℃或升至30℃、鹽度升至40該藻仍能緩慢增殖；溫鹽正交實(shí)驗(yàn)表明溫度、鹽度均在適宜的范圍內(nèi)才能實(shí)現(xiàn)紅色赤潮藻較快的生長，鹽度和溫度單方面的提高或降低都不適合其快速增殖。 （2）紅色赤潮藻可以吸收硝氮（NO3-）、銨氮（NH4+）無機(jī)氮源。實(shí)驗(yàn)范圍內(nèi)（10~200μM），該藻株生物量與NO3-濃度呈正相關(guān)關(guān)系；低濃度NH4+（10~100μM）可促進(jìn)藻細(xì)胞生長，而高濃度NH4+（200μM）會抑制藻細(xì)胞的生長，分析原因是高濃度的NH4+會產(chǎn)生極大的毒性，殺死藻細(xì)胞，從而影響了其比生長率。相對于NH4+，紅色赤潮藻更容易吸收NO3-。 （3）紅色赤潮藻可以吸收多種類型的有機(jī)氮源，如尿素（urea）、蛋白胨（peptone）、游離氨基酸。以尿素為唯一氮源時（100μM），其比生長率最高（~0.31d-1）；其次為組氨酸（his）和蛋白胨(0.17~0.18d-1)。相對于賴氨酸（lys）、谷氨酸（glu）、甘氨酸（gly），以組氨酸為唯一氮源時，其比生長速率最高。 （4）在其他營養(yǎng)鹽充足而N源脅迫的環(huán)境中，紅色赤潮藻可形成孢囊來適應(yīng)不良環(huán)境的脅迫。孢囊大小、形態(tài)與營養(yǎng)細(xì)胞不同。N脅迫條件下孢囊形成時間較早（2d），各處理組孢囊形成率約為8.77%~22.25%。硝氮（NO3-）、銨氮（NH4+）限制條件下孢囊最大密度分別為291、158cells/mL。
[Abstract]:In recent years, harmful algal blooms occur frequently along the coast of China, which pose a great threat to the coastal ecological environment and human health. The frequent occurrence of harmful algal blooms is closely related to environmental conditions and eutrophication and has become the focus of attention of researchers at home and abroad. Red tide algae (Akashiwo sanguinea) is one of the causes of harmful algal blooms. Researchers have done a lot of research on the hydrometeorological, biological and chemical factors during the algal blooming period, but little has been done on the growth of the algal population. The mechanism of algal blooms is still unclear. Therefore, it is of great significance to understand the population growth of red tide algae and its sporocyst formation mechanism in order to reveal the extinction of algal blooms caused by this species and its prevention and control. In this paper, the effect of main environmental factors and nitrogen forms on the population growth of red tide alga, a typical algal blooming species, in Yantai Bay of Yantai, was studied by means of one-off culture. The effects of nitrogen nutrient stress on the formation of spore sac were studied. The results showed that: (1) Red tide algae had a wide range of adaptation to temperature, salinity and light, the optimum growth temperature was 20 鈩

本文編號：2299988