Laws Edward A, Pei Shaofeng, Bienfang Paul, Grant Scott, Sunda William G
Department of Environmental Sciences, School of the Coast & Environment, Louisiana State University, Baton Rouge, Louisiana 70803, USADepartment of Oceanography, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96822, USABeaufort Laboratory, National Ocean Service, National Oceanic and Atmospheric Administration 101 Pivers Island Road, Beaufort, North Carolina 28516, USA.
J Phycol. 2011 Oct;47(5):1089-97. doi: 10.1111/j.1529-8817.2011.01040.x. Epub 2011 Aug 29.
The relationship between steady-state growth rate and phosphate concentration was studied for the marine prymnesiophyte Pavlova lutheri (Droop) J. C. Green grown in a chemostat at 22°C under continuous irradiance. A bioassay procedure involving short-term uptake of 10 picomolar spikes of (33) P-labeled phosphate was used to estimate the concentration of phosphate in the growth chamber. The relationship between growth rate and phosphate was well described by a simple rectangular hyperbola with a half-saturation constant of 2.6 nM. The cells were able to take up micromolar spikes of phosphate at rates two to three orders of magnitude higher than steady-state uptake rates. The kinetics of short-term uptake displayed Holling type III behavior, suggesting that P. lutheri may have multiple uptake systems with different half-saturation constants. Chl a:C ratios were linearly related to growth rate and similar to values previously reported for P. lutheri under nitrate-limited conditions. C:N ratios, also linearly related to growth rate, were consistently lower than values reported for P. lutheri under nitrate-limited conditions, a result presumably reflecting luxury assimilation of nitrogen under phosphate-limited conditions. C:P ratios were linearly related to growth rate in a manner consistent with the Droop equation for growth rate versus cellular P:C ratio.
研究了海洋定鞭藻鲁氏巴夫藻（Pavlova lutheri (Droop) J. C. Green）在22°C连续光照下于恒化器中生长时，稳态生长速率与磷酸盐浓度之间的关系。采用一种生物测定方法，即短期摄取10皮摩尔（33）P标记的磷酸盐脉冲，来估算生长室中磷酸盐的浓度。生长速率与磷酸盐之间的关系可用一条简单的矩形双曲线很好地描述，其半饱和常数为2.6 nM。细胞摄取微摩尔级磷酸盐脉冲的速率比稳态摄取速率高两到三个数量级。短期摄取动力学呈现出Holling III型行为，这表明鲁氏巴夫藻可能具有多个具有不同半饱和常数的摄取系统。叶绿素a:碳（Chl a:C）比值与生长速率呈线性相关，且与先前报道的鲁氏巴夫藻在硝酸盐限制条件下的值相似。碳:氮（C:N）比值也与生长速率呈线性相关，始终低于报道的鲁氏巴夫藻在硝酸盐限制条件下的值，这一结果可能反映了在磷酸盐限制条件下氮的奢侈吸收。碳:磷（C:P）比值与生长速率呈线性相关，其方式与生长速率相对于细胞磷:碳比值的Droop方程一致。
