氮、磷浓度对伪鱼腥藻生长及光合生理的影响

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（F_v/F_m、α、rETR_max、I_K）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K_sP，细胞内磷份额Q₀与对总氮的半饱和常数K_sN。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F_v/F_m、I_K有显著影响（P<0.05），而对rETR_max、α影响不显著（P>0.05）。K_sP?K_sN，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0.0486 μg/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。

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

The effects of nitrogen and phosphorus concentrations on the growth, chlorophyll fluorescence parameters (F_v/F_m、α、rETR_max、I_K) 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, K_sP of total phosphorus, intracellular phosphorus share and the semi-saturation constants K_sN 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 F_v/F_m、I_K and no significant effect on rETR_max, α (P>0.05). K_sP was far less than K_sN, which proved that Pseudanabaena sp. had better affinity for phosphorus. The minimum share of intracellular phosphorus for Pseudanabaena sp. was 0.0486 μg/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.