滇池水华束丝藻-Aphanizomenonflos-aquae-对低氮的生理响应

J．LakeSci．(湖泊科学)，2014，26(1):131-136http://www．jlakes．org．E-mail:jlakes@niglas．ac．cn2014byJournalofLakeSciences滇池水华束丝藻(Aphanizomenonflos-aquae)对低氮的生理响应*吴艳龙1，2，郑凌凌1，李林1，殷大聪3，代龚圆1，宋立荣1＊＊(1:中国科学院水生生物研究所淡水生态与生物技术国家重点实验室，武汉430072)(2:中国科学院大学，北京100049)(3:长江水利委员会长江科学院，武汉430010)摘要:通过对分离的滇池北部海埂湾春季蓝藻水华时期的两株水华束丝藻(Aphanizomenonflos-aquae)进行研究，探讨了滇池水华束丝藻在低浓度硝酸盐下的生长特征，以及无氮条件下藻丝异形胞的诱导分化过程与固氮能力．实验结果表明:两株水华束丝藻在各浓度硝酸盐中均能够生长，并且生物量能够增加到较高水平．硝态氮浓度高时水华束丝藻的生物量也较高，但是硝酸盐浓度超过0．5mg/L时，各组生物量无显著性差异．无氮BG-11培养基培养条件下，水华束丝藻可以快速分化形成异形胞，含有异形胞的藻丝比例在3d以后即可达50%左右，最高可以达72%，之后开始下降，但是仍能维持较高比例．水华束丝藻在无氮条件下通过异形胞固定的氮元素从第7d开始逐渐增加，在生长43d后，培养基中增加的氮浓度接近30mg/L．关键词:滇池;水华束丝藻;硝态氮;异形胞;固氮PhysiologicalresponsetolownitrogenlevelinAphanizomenonflos-aquaefromLakeDi-anchiWUYanlong1，2，ZHENGLingling1，LILin1，YINDacong3，DAIGongyuan1＆SONGLirong1(1:StateKeyLaboratoryofFreshwaterEcologyandBiotechnology，InstituteofHydrobiology，ChineseAcademyofSciences，Wuhan430072，P．Ｒ．China)(2:UniversityofChineseAcademyofSciences，Beijing100049，P．Ｒ．China)(3:WaterＲesourcesDepartment，YangtzeＲiverScientificＲesearchInstitute，Wuhan430010，P．Ｒ．China)Abstract:TwostrainsofAphanizomenonflos-aquaewereisolatedfromspringcyanobacterialbloomsinHaigengBaywhichlocatedinthenorthernpartofLakeDianchi．BoththegrowthcharacteristicsandheterocystformationaswellasnitrogenfixationabilityofA．flos-aquaewereinvestigatedunderdifferentlowconcentrationsofsodiumnitrate，andinnitrogen-freeculturemedium，respective-ly．TheresultsshowedthatA．flos-aquaestrainswereabletogrowintheBG-11mediumwithvariouslowconcentrationsofnitrate，andthebiomassreachedaveryhighlevel．Thebiomassincreasedwiththenitrate-nitrogenconcentrationincreasing，buttherewasnosignificantdifferencewhennitrate-nitrogenconcentrationwasabove0．5mg/L．InductionofheterocystdifferentiationwasrapidwhenA．flos-aquaewasculturedinN-deficientBG-11medium，andafterreachingamaximumof72%approximately，thefilamentwithheterocystbegantoswinglower．Thetotalnitrogeninnitrogen-freemediumincreasedgraduallyasnitrogenfixationproceed，andnitrogenconcentrationwasc