We evaluated the effect of illuminance (12 000, 8 000, and 4 000 lx), temperature (15℃, 20℃, and 25℃), salinity (31, 28, 24, and 20), and the ratio of nitrogen to phosphorus (50∶1, 10∶1, 5∶1, and 1∶1) on growth, apparent photosynthesis, dark respiration, and pigment content of the primary receptacles of Sargassum thunbergii collected from the Taipingjiao coast, Qingdao. We tested the influence of these factors in four single-factor experiments. The highest values for specific growth rate and apparent photosynthesis rate were observed in algal plants reared under 8 000 lx, 20℃ and salinity 20. Exposure to 12 000 lx significantly inhibited growth and photosynthesis. The specific growth rate at 15℃ was 50.64% lower than at 20℃ (P<0.05). The specific growth rate and apparent photosynthesis rate increased significantly when salinity decreased from 31 to 28. As illuminance and temperature increased, pigment content decreased. Chlorophyll a and carotenoid content were significantly influenced by the environmental factors, whereas levels of Chlorophyll c remained stable. The growth and photosynthesis of the primary receptacles was significantly influenced by the ratio of nitrogen to phosphorus. The range of suitable ratios was between 5∶1 and 1∶1. A ratio of 50∶1 resulted in inhibition of growth and photosynthesis. Changes in the concentration of phosphorus affected the photosynthesis of primary receptacles more significantly than did changes in nitrogen. Thus, phosphorus appears to be more important during the growth of reproductive organs in S. thunbergii than nitrogen. The ratio of nitrogen to phosphorus had no effect on the pigment content. Culture media that was rich in nitrogen or phosphorus had a beneficial effect on the ac-cumulation of pigment. Our results provide guidance for the optimization of artificial breeding technologies for S. thunbergii.% 鼠尾藻(Sargassum thunbergii)样本采自青岛太平角,以光照、温度、盐度及营养盐水平4项环境因子分别设置4组单因素实验,研究其对鼠尾藻生殖托的生长、表观光合作用、暗呼吸作用以及色素积累的影响。结果显示：(1)光照度为8000 lx、温度为20℃和盐度为20的条件下生殖托的比生长速率(SGR)较大,表观光合作用较强。光照12000 lx抑制生殖托的光合作用与生长,15℃下比生长速率比20℃小50.64%(P<0.05),盐度从31下降到28,比生长速率与表观光合速率显著增大。(2)色素含量与光照度、温度呈显著的负相关性,叶绿素 a 和类胡萝卜素含量受环境因子影响较大,而叶绿素 c 相对稳定。(3)氮磷营养盐的浓度配比对生殖托的生长、光合作用影响显著,适宜的氮磷比(N/P)范围为5∶1~1∶1,而50∶1显著抑制生殖托的生长。(4)相比氮元素而言,磷浓度变化对生殖托光合作用影响更大,说明磷元素对于生殖托的构建至关重要。(5)氮磷比对生殖托色素含量影响不显著,而富氮、富磷培养液有利于色素的积累。结果表明,上述4项环境因子对鼠尾藻生殖托的生长及光合特性均有显著影响,适宜的培养条件为光照度8000 lx、温度20℃、盐度20、氮磷浓度比(N/P)在5∶1~1∶1。本研究旨在为鼠尾藻人工育苗技术的优化提供科学依据。
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