氮、磷浓度对伪鱼腥藻生长及光合生理的影响

EFFECTS OF NITROGEN AND PHOSPHORUS CONCENTRATIONS ON GROWTH AND PHOTOSYNTHETIC PHYSIOLOGY OF Pseudanabaena sp.

以伪鱼腥藻(Pseudanabaena sp.)为研究对象,研究了不同氮、磷浓度对伪鱼腥藻生长、叶绿素荧光参数(Fv/Fm、α、rETRmax、IK)及类胡萝卜素与叶绿素a比值等的影响,并应用Monod和Droop方程考察氮、磷营养盐对伪鱼腥藻生长动力学的影响,分别计算得到伪鱼腥藻对总磷的半饱和常数KsP,细胞内磷份额Q0与对总氮的半饱和常数KsN。结果表明:氮、磷浓度对伪鱼腥藻的生长影响极显著(P<0.01),在氮浓度为0~230.4 mg/L内,伪鱼腥藻的生物量与氮浓度呈正相关,磷浓度>1.28 mg/L会抑制伪鱼腥藻生长。氮浓度对各叶绿素荧光参数有显著影响(P<0.05),磷浓度对Fv/Fm、IK有显著影响(P<0.05),而对rETRmax、α影响不显著(P>0.05)。KsP<<KsN,伪鱼腥藻对磷具有更好的亲和性,伪鱼腥藻能够正常生长的细胞最小内磷份额Q0为0.0486μg/mg,低于该值则藻细胞的增殖停止。类胡萝卜素与叶绿素a比值与氮、磷营养盐浓度呈负相关。

The effects of nitrogen and phosphorus concentrations on the growth,chlorophyll fluorescence parameters(Fv/Fm、α、rETRmax、IK)and the ratio of carotenoid to chlorophyll a of Pseudanabaena sp.were investigated.Moreover,the Pseudanabaena sp.growth kinetics utilizing nitrogen and phosphorus was demonstrated through Monod equation and Droop equation.The semi-saturation constants,KsP of total phosphorus,intracellular phosphorus share and the semi-saturation constants Ks N of total nitrogen were calculated.The results showed that the effects of different nitrogen and phosphorus concentrations on the growth of Pseudanabaena sp.were significant(P<0.01).The chlorophyll a of Pseudanabaena sp.was positively correlated with nitrogen concentration ranging from 0 to 230.4 mg/L,and phosphorus concentration higher than 5.12 mg/L inhibited the growth of Pseudanabaena sp.The chlorophyll fluorescence parameters were significantly affected by different nitrogen concentrations(P<0.05).Concentrations of phosphorus had a significant effect on Fv/Fm、IK and no significant effect on rETR max,α(P>0.05).KsP was far less than KsN,which proved that Pseudanabaena sp.had better affinity for phosphorus.The minimum share of intracellular phosphorus for Pseudanabaena sp.was 0.0486μg/mg,under which the proliferation of algal cells will cease.The ratio of carotenoid to chlorophyll a was negatively correlated with the concentration of nitrogen and phosphorus.