三角褐指藻在磷营养限制胁迫下的补偿生长效应

以三角褐指藻(Phaeodactylum tricornutum)为研究材料,设置了5个磷营养限制处理:磷营养分量分别设为f/2培养基的1/20(P₁)、1/10(P₂)、1/8(P₃)、1/4(P₄)、1/2(P₅),以f/2为对照(P_ck),在磷限制胁迫下培养10d,然后均以相同密度(2.5×10⁵cells·mL^-1)接种在f/2条件下恢复培养16d,测定了三角褐指藻在磷限制胁迫下和恢复培养阶段的生长状况。结果表明,三角褐指藻在受到磷限制胁迫后,细胞密度、蛋白质和可溶性糖含量都显著低于对照(p<0.05);恢复阶段,P₁、P₂和P₃处理组的细胞密度、平均相对生长率及生物量在恢复培养的中前期显著高于对照(p<0.05),最高平均相对生长率分别为0.73、0.70、0.68d^-1,显著高于对照(0.55d^-1)(p<0.05);P₄处理组的细胞密度和生物量与对照无显著差异;P₅处理组的细胞密度和生物量在恢复培养的中前期显著低于对照(p<0.05);随着培养时间的推移,各处理组与对照之间的差异逐渐缩小,处理组和对照的细胞密度、生物量、蛋白质和可溶性糖含量等均无显著差异。

Compensatory growth of Phaeodactylum tricornutum in response to the stress of phosphorus limitation

In this paper, Phaeodactylum tricornutum was used to study the compensatory growth of micro-algae under phosphorus limitation. Five P concentration levels were set up at 1/20(P₁), 1/10(P₂), 1/8(P₃), 1/4(P₄), 1/2 (P₅) of f/2 phosphorus media respectively, while f/2 culture media was served as control (Pck). P. tricornutum had been treated under phosphorus stress for 10 days, then, the nutrient stresses were removed by introducing f/2 media, the cultures were cultured for 16 more days with inoculative cell density (2.5×10⁵cells·mL^-1)and normal nutrients supply. Cell density, biomass, content of intracellular dissoluble carbohydrate and protein were measured during these two periods. It was found that cell density, biomass, content of intracellular carbohydrate and protein of P. tricornutum were lower than that of the control under phosphorus limitation (p<0.05). During the phosphorus recovery stage, cell density and biomass of P₁、P₂ and P₃ treatments were higher than those of the control during prophase and metaphase (p<0.05), and their maximal average relative growth rates were 0.73、0.70、0.68 d^-1 respectively, which were higher than that(0.55 d^-1) of the control(p<0.05). The difference of cell density and biomass between P₄ treatment and the control was not significant. The cell density and biomass of P₅ treatment were lower than control significantly during prophase and metaphase (p<0.05). As the culture time increased, the difference of cell density、biomass、content of intracellular protein and dissoluble carbohydrate between the treatments and the control trended to be equivalent.