Effect of Nitrogen on Growth and PhotosystemⅡ of Dunaliella salina
YANG Songqi;WANG Lijuan;XIE Ting;LUO Guanghong;ZU Tingxun;Hexi University,Gansu Engineering Technology Research Center for Microalgae,Key Laboratory of Hexi Corridor Resources Utilization of Gansu;
In order to investigate the response of growth and PSⅡ of Dunaliella salinato different nitrogen sources,we performed experiments by using NaNO3,CO(NH_2)_2,NaNO2,and NH4 Cl as nitrogen sources and-N control was set in this study.Our results showed that:(1)D.salinagrew faster under CO(NH_2)_2with a maximum growth rate[μmax,(0.482±0.032)/d]per day than under other nitrogen sources.(2)Results of chlorophyll fluorescence indicated no significantly different in the initial slope of the RLC before the onset of saturation(α),the maximum potential ETR(rETRmax),the maximum photochemistry efficiency(Fv/Fm),the maximum quantum yield of primary photochemistry(φP0),quantum yield for electron transport(φE0),probability(t=0)that a trapped exit on moves an electron into the electron transport chain beyond QA-(ψ0),absorption flux per RC(ABS/RC)and trapped energy flux per RC(t=0)(TR0/RC)among NaNO3,CO(NH_2)_2,and NaNO2groups(P0.05),while there is significantlydifferent in these parameters when compared with NH4 Cl and-N controls(P0.05).(3)Compared with the NaNO2,NaNO3,and CO(NH_2)_2groups,the relative variable fluorescence(Vj)of D.salinaincreased significantly under nitrogen free treatment(P0.05),which suggesting restriction of photosynthetic electron transport of D.salinafrom QA-to QBand accumulation of QA-.However,we can infer destroy of the oxygen evolving complex(OEC)of D.salina by the NH4 Cl from the appearance of K phase under NH4 Cl.As a whole,these results showed that D.salinagrew much faster under CO(NH_2)_2than that under NaNO3 and NaNO2,whereas the growth of D.salina was inhibited significantly by nitrogen deficiency,and the number of reactive centers in PS II was decreased,and the electron transport was blocked.However,toxicity effect of NH4 Cl on D.salinacaused its death in a short time and the OEC of D.salina was damaged.
【Fund】： 甘肃省科技支撑计划-社会发展类项目(1604FKC090);; 河西学院青年基金(QN2015-03)
【CateGory Index】： Q945
【CateGory Index】： Q945