不同氮磷营养条件下铜绿微囊藻（Microcystis aeruginosa）对正磷酸盐的蓄积效果

铜绿微囊藻是中国湖泊、水库及其它水域生态系统发生、形成富营养化危害的主要藻类。采用了直接显色法对单细胞铜绿微囊藻（〖WTBX〗Microcystis aeruginosa〖WTBZ〗）蓄积正磷酸盐的浓度进行测定，并与传统测定方法进行比较。直接显色法测定的磷浓度值减去溶液中可溶性磷浓度值即得到铜绿微囊藻蓄积的磷浓度值。对用不同处理方式处理过的铜绿微囊藻藻液进行过滤显色和直接显色测定，结果表明聚磷酸盐(正磷酸盐)在铜绿微囊藻体内不是游离存在，而很可能是与细胞内某一活性部分结合。在确立测定方法的基础上，研究了以修改了的MⅢ培养基为基本培养条件，改变氮磷浓度对产毒铜绿微囊藻（FACHB942）蓄积正磷酸盐效果的影响。结果显示，①氮磷比不变时，随着起始磷浓度的增加，铜绿微囊藻对正磷酸盐蓄积量也逐渐增加，成明显正相关；②氮浓度不变时，铜绿微囊藻对正磷酸盐的蓄积效果与磷浓度正相关；③而同一磷浓度下，铜绿微囊藻对正磷酸盐的蓄积效果与氮浓度负相关，但氮浓度超过21 mg/L时，氮浓度对于铜绿微囊藻蓄积磷的效果影响变得不规则。

PHOSPHATE UPTAKE IN UNICELLULAR MICROCYSTIS AERUGINOSA UNDER DIFFERENT NITROGEN AND PHOSPHORUS CONDITIONS

Microcystis aeruginosa,a kind of bloom algae,may cause severe damage in lakes,reservoirs and some other water bodies in China.In the present study,direct ammonium molybdate spectrophotometric method was used to measure the phosphate uptake of unicellular M.aeruginosa.The concentration of uptake phosphate was equal to the concentration value measured by ammonium molybdate spectrophotometric method after subtracted from dissoluble total phosphate.Comparing the results of three kinds of pre treatments (hydrochloric acid,ultrasonic fragmentation and frigorific fragmentation treatment),it is found that polyphosphate (phosphate) was not dissociated in cells of M.aeruginosa but associated with bio activity components of the cells.According to the determination method,the phosphorus uptake of M.aeruginosa,which was cultured in modified MIII cultures,was studied under different N,P concentrations.The results showed that:①Under constant N/P ratio,N/P=7/15,the accumulated quantity of phosphorus in M.aeruginosa increased with the increased initial P concentration in the media;②Under the constant N concentration,the phosphorus uptake of M.aeruginosa was correlated positively with the initial P concentration;③Under the constant P concentration,the accumulation of phosphorus by M.aeruginosa was correlated negatively with the initial N concentration,but the trend was not obvious and the effect of initial N concentration on the uptake P quantity became ruleless when the initial N concentration reached a higher level (21 mg/L).