缺磷胁迫后四尾栅藻在富磷环境中对磷的吸收动力学

研究了四尾栅藻(Scenedesmus quadricauda)受到不同程度缺磷胁迫后在富磷培养基中吸收磷的短期动力学过程,分析了磷在基质、细胞表面和细胞内的迁移变化过程.结果表明:经过0,30和60 h磷饥饿处理后的藻细胞,单个细胞内的磷含量分别为5.64×10-9,5.52×10-9和2.71×10-9mg;其在富磷培养基中的最大磷吸收速率分别为0.047×10-9,0.098×10-9和0.045×10-9mg/m in(以单细胞计);稳定时单个细胞内的磷含量分别为5.60×10-9,7.07×10-9和4.20×10-9mg.经0 h饥饿处理后的藻细胞在移入富磷培养基后短时间内出现明显的内磷释放过程,经30 h饥饿处理后的藻细胞对磷的"奢侈"吸收现象明显.此外,四尾栅藻细胞表面存在较明显的磷吸附现象,在磷充足环境中吸附量约占细胞总磷(表面吸附磷+细胞内磷)含量的1/10.

Phosphorous Absorption Dynamics of Starved Scenedesmus Quadricauda in Phosphate-replete Medium

Experiments were carried out to study the short-term phosphorus absorption dynamics of Scenedesmus quadricauda in phosphate-replete medium after different durations of phosphorus starvation. The transferring process of phosphorus among the medium, cell surface and cell quota were analyzed. The results showed that after phosphorus starvation of 0, 30 and 60 h, the cell-quotas of phosphorus were 5.64×10~(-9), 5.52×10~(-9), and 2.71×10~(-9) mg per cell respectively. The corresponding maximum absorption rates of phosphate per cell under experimental conditions were 0.047×10~(-9), 0.098×10~(-9) and 0.045×10~(-9) mg/min. The contents of cell interior phosphorus at equilibrium were 5.60×10~(-9), 7.07×10~(-9) and 4.20×10~(-9) mg per cell separately. When moved into a phosphate-replete culture medium, algal cells starved for 0 h experienced a fast process of internal phosphate release before absorption of phosphate, while "luxury consumption" was obviously observed in algal cells starved for 30 h. Also, obvious surface-adsorption of phosphorus was observed; the amount of adsorption was about 10% of the total cell phosphorus (including surface-adsorbed and cell-quota phosphorus) in the phosphorus-replete circumstances.