Variation in tolerance of Prorocentrum donghaiense Lu to N or P deficiency, and its compensatory growth under normal nutrient conditions (f/2 culture media) were studied. Two experimental treatments that included a nutrient deficiency period and a period without nutrient stress, were conducted. First, P. donghaiense was cultured for 10 days under nutrient stress that included, poor nutrients, N deficiency, P deficiency, and N plus P deficiency, while normal nutrient conditions (f/2 culture media) served as a control. Second, nutrient stress was removed, and the treated and control groups were cultured for another ten days at the same inoculation density and a sufficient nutrient supply, si-multaneously. Cell density, growth rate, relative growth rate, generation time and Chlorophyll-a was determined during the two periods. The results indicated that nutrient stress has an inhibitory effect on cell growth. Phosphorus deficiency had the least inhibitory effect, whereas N plus P deficiency had a comparatively large inhibitory effect. There was a significant difference (P<0.05) in the growth condition of algal cells between the treated and control groups. Maximum cell densities of the control, poor nutrients, N deficiency, P deficiency, and N plus P deficiency groups were 83×104 cell·mL–1, 32×104 cell·mL–1, 43×104 cell·mL–1, 78×104 cell·mL–1 and 29×104 cell·mL–1, respectively. Maximum growth rates were 0.64 d–1, 0.53 d–1, 0.61 d–1, 0.54 d–1and 0.51 d–1;maximum average relative growth rates were 0.61 d–1, 0.39 d–1, 0.44 d–1, 0.44 d–1and 0.35 d–1;minimum generation times were 1.13 d, 1.76 d, 1.58 d, 1.58 d and 2.00 d, and maximum chlorophyll-content a was 723.7μg·μL–1, 286.4μg·μL–1, 427.1μg·μL–1, 694.2μg·μL–1 and 292.9μg·μL–1, respectively. During the periods when nutrient stress was removed, it was found that after being subjected to nutrient stress, P. donghaiense had the ability of compensatory growth, particularly in the P deficiency treatment. There was a significant difference (P<0.05) in the growth condition of algal cells between the treated and the control groups. The main charac-teristic of compensatory growth of P. donghaiense was that the treated group had a higher average relative growth rate, a greater number of cells, and higher chlorophyll-a content than the control group in the initial culture time. In addition, the maximal rate range of net cell increase was 0.30%–80.95%, and the generation time of the cells was shorter. As the culture time proceeded, the difference between the treated group and the control group decreased. Eventually, all para-meters of the treated and control groups were similar. These results showed that P. donghaiense has over-compensatory growth under conditions of nutrient stress, particularly during P deficiency. This might be the cause of harmful algal blooms in the China Seas, which are P deficient year-round.%以长江口及其邻近海域最重要的甲藻赤潮生物种东海原甲藻(Prorocentrum donghaiense Lu)为研究材料,观察其对氮、磷营养限制胁迫的耐受程度以及恢复营养条件下补偿生长的情况。研究实验分营养限制和恢复营养两个阶段进行,每个阶段均设置对照组、贫营养组、限氮组、限磷组和限氮限磷组。研究结果显示,在氮、磷营养限制胁迫下,东海原甲藻生长受到抑制,其中磷限制对藻细胞生长的抑制作用最小,氮磷共同限制的抑制作用最大。限磷组最大细胞密度为78×104 cell·mL–1,与对照组无显著差异(P>0.05),但显著高于其他处理组(P<0.05)。细胞各项生长参数和叶绿素a的含量,与细胞密度类似,其中限磷组的最大细胞日生长速率、最大平均相对生产率、最小细胞代时、最大叶绿素a含量分别为0.61 d–1、0.44 d–1、1.58 d和694.2μg·μL–1,与对照组无显著差异(P>0.05),而与其他处理组则有显著差异(P<0.05)。藻细胞所受到抑制作用随着培养时间的推移而加强。后期,限磷组和其他处理组的细胞密度均显著低于对照组(P<0.05),处理组各细胞参数均显著劣于对照组(P<0.05)。在恢复营养的培养前期,4个经过营养限制处理组的生长情况均显著优于持续营养正常条件下培养的对照组(P<0.05)。表明东海原甲藻细胞表现出较强的超补偿生长能力,其中磷限制后表现出的超补偿能力最强。由此可知,东海原甲藻补偿生长的主要特征表现为,在恢复营养培养后,各处理组比对照组细胞数增多,叶绿素a含量增高,细胞日生长速率和平均相对生长率提高,细胞数净增率高达10.30%~80.95%,细胞代时缩短。根据研究结果认为,东海原甲藻具有较强的耐受低磷能力,而在营养条件恢复情况下,经历低磷胁迫的东海原甲藻又具有最强超补偿生长能力,使得其在与硅藻竞争中居于优势,这是东海原甲藻赤潮在中国沿海海域频繁暴发的原因之一。本研究旨在为揭示长江口及其邻近的东海海域甲藻赤潮逐年大规模暴发机理以及硅藻与甲藻赤潮种的演替现象提供依据。
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