纳米银对小球藻光合作用和呼吸作用的影响

使用硼氢化钠还原硝酸银,聚乙烯醇(PVA)作为分散剂,制备出粒径为(7 ± 3)nm的纳米银,分别使用计数法和溶解氧法,研究了纳米银对小球藻(Chlorella vulgaris)生长、光合作用和呼吸作用的影响,并调查了对叶绿素a的抑制状况.结果显示,黑暗条件下加入3mg/L的纳米银,基本抑制了小球藻的呼吸作用,当暴露于4mg/L的纳米银时,小球藻生长的抑制率为93%;而光照条件下加入10mg/L纳米银时,才能抑制其光合作用,此时对小球藻生长的抑制率达到90%.光照时,叶绿素a在10mg/L纳米银的作用下,抑制率达到77%.研究表明了纳米银对小球藻呼吸作用有很强的抑制作用,对光合作用的影响可能通过抑制叶绿素a的合成或破坏叶绿体的结构来完成;光照能够明显减弱纳米银的毒性.

Effects of silver nanoparticles on photosynthesis and respiration of Chlorella vulgaris

Silver nanoparticles (AgNPs) were synthesized via the reduction of silver nitrate by sodium borohydride and stabilized by polyvinyl alcohol, and the particle size was (7 ± 3) nm. The effects of AgNPs on the growth, photosynthesis, and respiration of Chlorella vulgaris were studied using the methods of cell count and oxygen uptake and production rates, and the inhibition of chlorophyll a was also investigated. The respiration of Chlorella vulgaris was completely inhibited by AgNPs of 3mg/L in 2h, and inhibition rate of the growth was 93% by AgNPs of 4mg/L when AgNPs were added in the dark. However, when AgNPs were added in the light, the photosynthesis of Chlorella vulgaris were inhibited when AgNPs of 10mg/L were used, and under this condition, inhibition rate of the growth reached 90%. In addition, 77% of chlorophyll a was inhibited by 10mg/L AgNPs. AgNPs had a strong effect on respiration of Chlorella vulgaris and might inhibit the synthesis of chlorophyll a or destroy the structure of chloroplast to inhibit the photosynthesis. The light could obviously reduce the toxicity of AgNPs.