营养盐恢复对氮磷饥饿铜绿微囊藻生长的影响

在自然水体中微囊藻经常经历营养盐的限制和再补充,营养盐浓度的波动影响着微囊藻的生长和暴发.本文利用14C标记和荧光定量PCR研究了营养盐恢复对氮磷饥饿的铜绿微囊藻细胞生理和光合作用相关基因表达的影响.结果表明经过氮磷饥饿的铜绿微囊藻在补充营养盐后,都能快速生长,氮饥饿的藻细胞生长更快,但其经过快速增长期后很快开始衰亡.补充营养盐后,经过磷饥饿的藻细胞固碳能力和光合作用相关基因表达很快恢复至未经饥饿藻细胞的水平,而经过氮饥饿的藻细胞其固碳能力和相关基因虽然有很大提升,却难以恢复至未经饥饿的藻细胞的水平.这可能也是氮饥饿的藻细胞在饥饿解除后虽然能暂时地快速生长,但很快又进入衰亡的原因之一.

Nutrients Recovery on the Growth of Nitrogen and Phosphorus Starved Microcystis aeruginosa

Microcystis in natural water bodies may frequently go through periods of nutrient limitation and then may recover when the limited nutrient becomes available. We investigated changes in cell physiology and expression of photosynthesis-related genes during the recovery of Microcystis aeruginosa from nitrogen starvation and phosphorus starvation with the method of ¹⁴C isotope and fluorescent quantitative PCR. Our results suggested that Microcystis cells relieved from N starvation and P starvation resumed growth within 24 h and displayed significantly higher growth rates than not-starved-cells in the first 48 h. Carbon production rates and the expression levels of photosynthesis-related genes all increased rapidly after relieving from N starvation and P starvation in different degrees, enabling the rapid recovery from nutrient starvation. However, N-starved cells can not resume their cellular activity to full capacity when N became available and the damage of N deficiency to M. aeruginosa was unrecoverable, whereas cellular activity of P-starved cells could recover to normal properties.