无机磷对多甲藻生长及叶绿素荧光的影响

Effect of Inorganic Phosphorus on the Growth and Chlorophyll Fluorescence of Peridinium umbonatum

磷通常被认为是水体藻类生长第一限制因子,水体中磷的质量浓度对藻类生长与光合作用有着重要的影响.多甲藻(Peridinium umbonatum)是淡水甲藻水华常见的种类,而磷对其影响的研究甚少.以多甲藻为研究对象,探讨不同质量浓度无机磷源对多甲藻的生长及叶绿素荧光的影响.结果表明,随着无机磷质量浓度的增加,多甲藻的吸光度(OD)也增加.从培养期的第11d开始,磷质量浓度为0.1和0.6 mg/L处理下的多甲藻的OD值高于无磷(0 mg/L)与低磷(0.005,0.02 mg/L)处理.叶绿素荧光动力学参数结果发现,当磷质量浓度为0.005mg/L与0.02mg/L时,PSII单位反应中心(RC)耗散掉的能量(DI_0/RC),单位反应中心捕获的并用于还原QA的能量(TR_0/RC),单位反应中心传递到电子传递链末端的能量(RE_0/RC),单位面积(CS)吸收的光能(ABS/CS_0),单位面积的热耗散(DI_0/CS_0),单位面积捕获的光能(TR_0/CS_0),单位面积电子传递的量子产额(ET_0/CS_0),单位面积传递到电子传递链末端的能量(RE_0/CS_0),吸收的能量传递到电子链末端的量子产率(R_0)与无磷处理组差异无统计学意义.而磷质量浓度高于0.1mg/L时,荧光参数与无磷处理组差异有统计学意义(p<0.05).这些结果表明了高磷处理(0.1,0.6mg/L)显著促进了多甲藻的生长与光合作用,而无磷与低磷条件则对甲藻的生长与光合产生一定胁迫,也暗示了磷质量浓度的变化可能影响多甲藻水华的发生及过程.

Phosphorus is usually considered as a key limiting factor on algae growth,because it has a great effect on the growth and photosynthesis of algae.Peridinium umbonatumis a common bloom-forming species of freshwater dinoflagellates,but few studies are devoted to the understanding of the effect of phosphorus on it.In this study,P.umbonatum was cultured at different concentrations of inorganic phosphorus in order to explore the influences of phosphorus on its growth and chlorophyll fluorescence.The results indicated that the value of OD was enhanced with the increase of inorganic phosphorus concentration.After 11-day culture,OD in P.umbonatum at 0.1 and 0.6mg/L phosphorus was significantly higher than that in the treatments at no and low phosphorus（p〈0.05）.The chlorophyll fluorescence kinetics parameters showed that no significant differences existed between the treatments of 0.005mg/L or 0.02mg/L and 0mg/L in DI_0/RC,TR_0/RC,RE_0/RC,ABS/CS_0,DI_0/CS_0,TR0/CS0,ET0/CS_0,RE_0/CS_0 and R_0,while significant differences were detected between no-P and the treatments of≥0.1mg/L in these parameters（p〈0.05）.These results suggested that rich phosphorus significantly promoted the growth and photosynthesis of P.umbonatum,while no and low phosphorus had a negative influence on it.This also implied that the changes of phosphorus concentration might affect the formation and process of Peridinium blooms.