海头红的海水铁含量适宜性

Analysis on suitability of seawater iron concentration for Plocamium telfairiae

20℃条件下,研究了6个不同海水铁含量处理[23（自然海水,对照）、100、300、500、700、900μg·L^-1海头红（Plocamium telfairiae）相对生长速率、藻胆蛋白含量及过氧化物酶和固氮酶活力的影响,分析了海头红的海水铁含量适宜性。结果表明：经30 d培育实验,海水铁含量为100μg·L^-1理组海头红的相对生长速率（RGR）达到最大值（1.14%·d-1）,极显著高于其他海水铁含量处理组（P〈0.01）,而海水铁含量为300~900μg·L^-1理组海头红的RGR在0.26~0.34%·d-1,与对照组无明显不同（P〉0.05）;海头红3种藻胆蛋白含量均随海水铁含量的增加呈先增加后缓慢下降的变化趋势,并于100μg·L^-1达到最大值,海头红过氧化物酶活力亦在海水铁含量100μg·L^-1件下达到最高值（14.5U·mg^-1）,显著高于其他处理组（P〈0.05）,但不同海水铁含量对海头红固氮酶活力无显著影响（P〉0.05）。适宜性分析表明,在设定的5个海水富铁处理中,100μg·L^-1含量对海头红的促生长作用最显著。

The effects of different seawater iron concentrations [ 23 （ natural seawater, control）, 100, 300, 500, 700, and 900μg·L^-1] on relative growth rate, phycobiliprotein content, per- oxidase activity, and nitrogenase activity of Plocamium telfairiae were examined at 20 ℃ under controlled laboratory conditions to determine the suitability of seawater iron concentration for P. telfairiae during a period of 30 days. The results showed that the greatest relative growth rate （RGR） attained was 1.14 % · d^-1 under the 100μg·L^-1 treatment, which was significantly higher （P〈0.01） than those attained under other treatments. RGR of P. telfairiae ranged from 0.26 % · d^-1 at 900 μg·L^-1 to 0.34 % · d^-1 at 500 μg·L^-1 with an average of 0.30 % ·d^-1 , which showed no significant difference compared with that attained in control treatment （P〉0.05）. The contents of three phycobiliproteins exhibited a similar variation pattern, increas- ing significantly with the seawater iron concentration increasing from 23 to 100 μg·L^-1 and de- creasing gradually with the seawater iron concentration increasing from 100 to 900 μg·L^-1. The greatest peroxidase activity was 14.5 U ·mg^-1 in the 100 μg·L^-1 treatment, which was signifi- cantly higher than those attained in the other treatments （P〈0.05）. However, no marked differ- ence was found in nitrogenase activity among different seawater iron concentration treatments （P〉 0.05）. Suitability analysis suggested that growth of P. telfairiae was significantly promoted by sea- water iron concentration of 100μg·L^-1 as compared to the higher iron enrichment in seawater （300-900 μg·L^-1 ）.