不同磷初始浓度对紫萍生长及磷吸收效率的影响

采用室内模拟培养试验方法,研究不同磷初始浓度对紫萍生长及磷吸收效率的影响。结果表明,水体初始ρ（磷）为3.0 mg.L-1时,紫萍相对生长率最高,生长繁殖速度最快。当初始ρ（磷）为0.3～3.0 mg.L-1时,紫萍对水体中磷的去除率在70%以上。紫萍累积吸磷量和磷吸收能力均随磷初始浓度的升高而增加,但当初始ρ（磷）为45.0 mg.L-1时,紫萍累积吸磷量和单位鲜质量紫萍吸磷量均明显下降。当初始ρ（磷）≤1.5 mg.L-1时,紫萍体内酸性磷酸酶活性升高,但随着低磷胁迫时间的延长,低磷条件和高磷条件间酸性磷酸酶活性差异减小。

Effect of Initial Phosphorus Concentration on Growth and Phosphorus Uptake of Spirodela polyrrhiza

Effects of initial phosphorus concentration in water on growth and phosphorus uptake of Spirodela polyrrhiza was investigated through an artificial culture experiment in laboratory.Results show that in the water with an initial phosphorus concentration being 3.0 mg·L-1 Spirodela polyrrhiza grew and multiplied the fastest,maintaining the highest relative growth rate.The phosphorus removal rate reached beyond 70% when the initial phosphorus concentration in the solution ranged between 0.3 and 3.0 mg·L-1.Both its cumulative phosphorus uptake and its phosphorus absorption rate increased with the increase in initial phosphorus concentration in water.However,drops began to appear in cumulative phosphorus uptake and phosphorus uptake per unit of mass of fresh Spirodela polyrrhiza when it grew in the water with an initial phosphorus concentration reaching 45.0 mg·L-1.When the plant grew in water with an initial phosphorus concentration being lower 1.5 mg·L-1,its ACPase activity increased,but its longer exposure to low phosphorus stress would narrow the difference in ACPase activity between treatments of low and high initial phosphorus concentrations.