铜绿微囊藻对紫外辐射的生理代谢响应  

Physiological response of Microcystis to solar UV radiation

作　　者：汪燕[1] 李珊珊[1] 李建宏[1] 邓洁[1] 潘澄[1] 李朋富[2] 

机构地区：[1]南京师范大学生命科学学院,江苏省生物技术和生物多样性重点实验室,南京210046 [2]南京大学生命科学学院,南京210093

出　　处：《生态学报》2011年第21期6532-6539,共8页Acta Ecologica Sinica

基　　金：国家重点基础研究发展计划973项目(2008CB418004)

摘　　要：采用紫外(UV)滤膜过滤日光UV以及紫外灯添加UV的方法,研究了UV辐射对铜绿微囊藻Microcystis aeruginosa单细胞藻株PCC7806和群体藻XW01生长及生理代谢的影响。结果显示,在室内条件下低剂量UV辐射可促进群体微囊藻XW01生长;室外条件下与滤除了UV的光照相比,含有UV的完全日光更有利于微囊藻生长;而相同的UV辐射强度均导致单细胞株死亡,群体株显示了较强的UV抗性;日光中的UV可促进XW01合成抗氧化相关的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)、促进胞外多糖的产生并形成较大的群体、促进UV屏障物质类菌孢素氨基酸(MAAs)和伪枝藻素(Scy)积累。这些生理代谢的改变,消除了阳光辐射中UV对微囊藻的伤害。研究的结果提示,自然条件下阳光中的UV有助于群体微囊藻生长。Toxic cyanobacteria Microcystis blooms often occur in eutrophic lakes around the world.During bloom-occurring,Microcystis population aggregates at the surface of water and is often exposed to strong UV radiation of sunlight.To evaluate the ecological function of solar UV on Microcystis bloom,we studied effects of UV radiation on two M.aeruginosa strains,the unicellular strain PCC7806 and the colonial strain XW01,by using a transparent UV protection film filtering out the solar UV from sunlight（cut off more than 90% UV radiation,＂without UV＂） in outdoor-culture,and using a 30 W UV lamp（1.25 μW/cm2 at the surface of culture medium） adding artificial UV radiation in lab-culture.Results showed that the growth of XW01 in the whole solar light（the highest intensity of UV-297 and UV-254 was about 120 μW/cm2 at noon,＂with UV＂） was better than in the light without UV in the outdoor-culture condition;the cell density（OD650nm） of 6-day culture with UV was 35.8% higher than that without UV.In the lab condition,the low-intensity artificial UV at 18.75 J/m2 daily radiation（repeat 5-second UV light with 20-second intervals,30 cycles） improved the growth of XW01,the cell density of 6-day culture was 14.5% higher than the control（without UV）.However,the same UV intensities killed the strain PCC7806 both of in the lab and outdoor experiments.These data show that a suitable UV radiation increase the growth of colonial XW01,and the colonial strain has a stronger resistance to UV than the unicellular strain. To discover the mechanism of XW01 against UV,we investigated the changes of antioxidant protective enzymes superoxide dismutase（SOD） and catalase（CAT） in XW01 cultured with or without solar UV.The activities of SOD and CAT of XW01 cultured with solar UV were 86% and 34% above that without solar UV respectively.However,the same solar UV decreased the activities of SOD and CAT of PCC7806 by 42% and 39% respectively and caused the cell death.The data indicate that XW01 has stronger antioxida

关 键 词：紫外辐射 微囊藻 群体 多糖 抗紫外 

分 类 号：X173[环境科学与工程—环境科学]