铝影响海洋固氮蓝藻.PDFVIP

铝影响海洋固氮蓝藻（Crocosphaera watsonii ）固氮速率的探究 The Effect of Aluminum on the Nitrogen Fixation of Crocosphaera watsonii 卢一平 吴起澜 毕晓曈 1 摘要：大气沉降向海洋表层输入大量的铝，然而少有研究报道铝对海洋浮游植物尤其固氮生 物的影响。我们以 Aquil 培养基（无氮硅营养盐）半连续培养一种海洋单细胞固氮蓝藻 15 （Crocosphaera watsonii ），利用流式细胞技术、 N 同位素示踪法和荧光PCR 定量分析，研究 不同磷浓度水平下铝 （0、0.2、2 和20μM ）对其生长速率和固氮速率的影响。实验结果表明： 在磷酸盐充足的条件下，铝处理组中该固氮蓝藻的生长速率和固氮速率明显受到抑制；而在磷 酸盐缺乏条件下，铝处理组中该固氮蓝藻的生长速率和固氮速率都明显增加。研究同时表明， 在磷充足和缺乏条件下，磷结合基因pstS 表达分别上调和下调，表明铝可能通过影响该固氮 蓝藻对磷的吸收进而影响其生长和固氮。 关键词：铝；单细胞固氮蓝藻；Crocosphaera watsonii；固氮作用 2 Abstract: Large amount of aluminum is input into the ocean through atmospheric dust deposition every year, however, few studies have reported that the effect of aluminum on marine phytoplankton, especially on the nitrogen-fixing cyanobacteria. In this study, a unicellular marine nitrogen-fixing cyanobacterium Crocosphaera watsonii was grown in Aquil medium without 15 silicate and nitrogen by semi-continuous cultures. Using flow cytometry and N isotope tracer method, we studied the effect of aluminum (0, 0.2, 2 and 20μM) on the growth and nitrogen fixation of Crocosphaera watsonii. Data showed that aluminum inhibited the growth and nitrogen fixation of Crocosphaera watsonii in phosphorus replete medium; While aluminum stimulated the growth and nitrogen fixation of Crocosphaera watsoni in low phosphorus medium. Data also showed that the expression of the high-affinity phosphate binding protein pstS treated with aluminum significantly were lower and higher in P-replete and