海马齿对不同盐度水质的碳汇作用以及不同形态氮利用的研究

为探讨海马齿(Sesuvium portulacastrum)对水域环境修复作用,本文研究了水培海马齿对不同盐度水质的碳汇作用以及不同形态氮的利用情况。实验设计0、10、20、30、35盐度梯度,海马齿水培时间82 d,然后测定植株干重、营养元素含量以及积累速率,最后在抑菌与不抑菌条件下研究海马齿根际与铵态氮(NH₄⁺-N)、硝态氮(NO₃^--N)、无机磷(PO₄^3-)以及色氨酸(Trp)吸收转化关系。研究结果表明,盐度10条件下海马齿植株干重、有机元素含量以及积累速率最高,有机碳、有机氮与有机磷积累速率分别为(5.572±1.611)、(0.313±0.058)、(0.057±0.013)mg/(d·ind.),而高盐环境35盐度条件下对海马齿生长造成一定胁迫。盐度0～35范围,海马齿均未出现死亡现象。不同盐度抑菌培养条件下,色氨酸与无机氮共存时均能被能被海马齿利用,色氨酸利用量远高于硝态氮、铵态氮;不抑菌条件下铵态氮则表现出增加的结果。海马齿作用在盐度...

EFFECT OF SALINITY ON CARBON SEQUESTRATION BY SESUVIUM PORTULACASTRUM AND UTILIZATION OF NITROGEN IN DIFFERENT FORMS

To understand S. portulacastrum growth and relationship between S. portulacastrum and nitrogen utilization under different salinity conditions, an 82-day hydroponic experiment in five salinity treatment groups (0, 10, 20, 30 and 35) were conducted, during which plant dry weight, nutrient elements content, and accumulation rate in S. portulacastrum were recorded, and then the variation in content changes of ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), inorganic phosphorus (PO₄^3-), and tryptophan (Trp) in S. portulacastrum rhizosphere were analyzed under bacteriostatic and non-bacteriostatic conditions. Results show that both accumulation of nutrient elements and the accumulation rate in S. portulacastrum were the highest at salinity 10, and the accumulation rates of organic carbon, organic nitrogen, and organic phosphorus reached (5.572±1.611), (0.313±0.058), and (0.057±0.013) mg/(d·ind.), respectively. High salinity 35 brought pressure on the S. portulacastrum growth and no mortality occurred in salinity range of 0~35. Under different salinities, S. portulacastrum utilized preferentially organic nitrogen and nitrate nitrogen as nitrogen sources. However, the absorption of organic nitrogen was inhibited at a higher salinity of 20~35. Under bacteriostatic condition at different salinities, S. portulacastrum could utilize both tryptophan and inorganic nitrogen, and tryptophan utilization was much higher than nitrate nitrogen and ammonium nitrogen. The ammonium nitrogen content showed an increase in the non-bacteriostatic condition. Tryptophan utilization of S. portulacastrum at salinity 10 under non-bacteriostatic conditions were the highest, reaching (3.33±1.68), (6.84±2.57), and (12.67±2.54) mg at 1 d, 3 d, and 5 d, respectively. This study provided a basis for the utilization of inorganic and organic nitrogen in mariculture environment on S. portulacastrum floating bed, and rich scientific data for floating bed design in different salinity culture environment.