Fe^(3+)对赤潮异弯藻生长和光合作用的影响

EFFECT OF Fe^(3+) ON GROWTH AND PHOTOSYNTHESIS OF MARINE RED TIDE ALGAE HETEROSIGMA AKASHIWO

用人工海水APSW以f/2营养加富 ,在总铁浓度为 0～ 10 0 0nmolL-1的范围内 ,考察了总铁浓度对赤潮异弯藻 (Heterosigmaakashiwo)生长和光合作用的影响 .结果发现 ,当铁浓度小于 10nmolL-1时 ,最大藻细胞密度与比生长速率均受到明显限制 .补铁后受铁限制的细胞得到缓解 ,表明铁是藻细胞生长的重要限制因子 .当铁浓度大于 10 0nmolL-1时 ,最大细胞密度与比生长速率不再受铁限制 ,但其光合作用活性有所改变 .在铁限制下细胞的光饱和光合作用速率Pm,暗呼吸速率Rd,表观光合作用效率α与铁丰富细胞相比都有所减小 ,而光补偿点Ic及饱和光强Ik增大 .图 5表 1参

Heterosigma akashiwo , a typical strain of red tide algae, grea in artificial seawater medium (APSW), supplemented with f/2 nutrients and trace metals at (22±0.5) ℃ with a series of Fe concentrations between 0～1 000 nmol L -1 . Cell final yields and exponential specific growth rate were limited when Fe was below 10 nmol L -1 and alleviated by addition of 100 nmol L -1 Fe. By comparison with the results under Fe replete condition, chlorophyll a specific and cell specific light saturated net photosynthetic capacity ( P m ), dark respiration rate ( R d ) and apparent photosynthetic efficiency ( α ) decreased proportionately, whereas the cells became light saturated at higher irradiance under Fe stress. Fig 5, Tab 1, Ref 11