中文摘要：

研究不同营养盐条件对龙须菜（Gracilaria lemaneiformis）的生理效应,对深入了解龙须菜与近海环境的相互作用具有重要意义。在低氮低磷（LNLP）、低氮高磷（LNHP）、高氮低磷（HNLP）和高氮高磷（HNHP）4种营养盐条件下培养龙须菜15d,以探讨不同氮、磷水平对龙须菜生长和光合特性的影响。结果表明：1）LNHP、HNLP和HNHP处理促进了龙须菜的生长,其中HNHP处理下龙须菜具有最大的相对生长速率和生物量;2）LNHP、HNLP和HNHP处理提高了龙须菜的光合无机碳利用能力,其中HNHP处理下龙须菜具有最大的无机碳饱和光合速率和表观半饱和常数,比LNLP处理分别提高了118%倍和48.71%;3）LNHP、HNLP和HNHP处理显著影响龙须菜的光化学效率,与LNLP处理相比,LNHP处理提高了龙须菜的光化学效率,而HNLP和HNHP处理降低了龙须菜的光化学效率。研究结果表明,HNHP处理条件下,龙须菜的生长和光合无机碳利用能力最高,光化学效率最低。

英文摘要：

Aim Our objective was to investigate the impacts of different nutrient levels on the physiology of Gracilaria lemaneiformis to evaluate the relationship between this mariculture species and costal environment. Methods Thalli of Gracilaria lemaneiformis were cultured for 15 days under four different nutrient conditions （low N and low P,low N and high P,high N and low P,and high N and high P） to examine the possible effects of the availability of different nutrients on growth and photosynthesis in this alga. Important findings Growth of G. lemaneiformis was enhanced with the low N and high P treatment,high N and low P treatment,and high N and high P treatment,compared to low N and low P treatment. The highest relative growth rate （RGR） and biomass were observed under high N and high P treatment. Gracilaria lemaneiformis was capable of using HCO3–as a source of exogenous inorganic carbon （Ci） for its photosynthesis,and the ability was increased at the above three nutrient conditions. Both car-bon-saturated photosynthetic rate and apparent half saturation constant under high N and high P treatment were significant higher than those under low N and low P treatment by 118% and 48.71%,respectively. Photochemical efficiency of G. lemaneiformis was stimulated with low N and high P treatment,but was inhibited at the two high N treatments. Thus,the rates of growth and photosynthesis were the highest,but the photochemical efficiency was the lowest in G. lemaneiformis grown under high N and high P treatment.