不同氮磷水平下微小原甲藻对营养盐的吸收及光合特性

研究了微小原甲藻对无机氮、磷的吸收特性和在室内批量培养条件下，无机氮、磷浓度对微小原甲藻生长和光合作用的影响. 结果表明，低氮(0.0882 mmol/L NaNO3)条件下，微小原甲藻具有最高的比生长速率，为0.46 d 1，而中氮(0.882 mmol/L NaNO3)条件下具有最大的细胞密度，为54900个/mL，分别比低氮和高氮(2.646 mmol/L NaNO3)下增加7.2 和20.1 . 随着培养基中磷浓度的升高，最大细胞密度和比生长速率也增加，在高磷(0.108 mmol/L KH2PO4)条件下达到最大值，分别为57400个/mL和0.45 d 1. 高营养源(高氮或高磷)状态下生长的藻细胞具有更高的单位细胞和单位叶绿素a表示的光饱和的光合作用速率(Pmchl a和Pmcell)和光饱和点. 低氮和高氮条件下的藻细胞同样具有高的单位细胞和单位叶绿素a表示的光合效率( chl a和 cell)，而单位叶绿素a表示的光合效率( chl a)则在高磷下最大. 在氮源充足条件下，低的N/P有利于微小原甲藻细胞的生长.

Photosynthetic Characteristics of Prorocentrum minimum and Its Nutrient Uptake at Different Nitrogen and Phosphorus Levels

The uptake of nitrate and phosphate by Prorocentrum minimum and its growth and photosynthesis characteristics were studied by laboratory culture. The results indicated that the maximum specific growth rate (0.46 d-1) was observed at low nitrate level (0.0882 mmol/L NaNO3), the maximum yield (54900 cell/mL) occurred at middle nitrate level (0.882 mmol/L NaNO3), which increased by 7.2% and 20.1% respectively compared with those at low nitrate and high nitrate levels. The cell yield and specific growth rate increased with increasing phosphate concentrations in culture, and the maximum cell yield (57400 cell/mL) and the maximum specific growth rate (0.45 d-1) were recorded at high phosphate concentration (0.108 mmol/L KH2PO4). The higher chlorophyll a-specific and cell-specific light-saturated photosynthetic rates (Pmchl a and Pmcell) and higher light intensity at which photosynthesis is initially saturated were observed at high nutrient levels. The cells grown in the cultures with low nitrate and high nitrate levels showed the same values of apparent photosynthetic efficiency (achl a and acell). The maximum chlorophyll a-specific apparent photosynthetic efficiency (achl a) was obtained at high phosphate level. The experimental results showed that the lower ratio of N/P with sufficient nitrate had a positive effect on the propagation of Prorocentrum minimum.