28611.陽光紫外輻射和co,2加富對硅藻小新月菱形藻的影響

1、汕頭大學碩士學位論文陽光紫外輻射和CO加富對硅藻小新月菱形藻的影響姓名：吳曉娟申請學位級別：碩士專業(yè)：海洋生物學指導教師：高坤山20090501汕頭大學碩士學位論文IIAbstractImpactsofincreasedsolarultravioletradiationatmosphericCO2riseoceanacidificationcausedbyindustrialactivitiesaresupposedtoaffectma

2、rineprimaryproductivityofwhichmarinediatomsareknowntocontributebyabout40%.ConsequentlyitisofsignificancetoinvestigatehowthediatomsrespondtothechangesinUVradiationCO2concentration.Therefethisthesiswasaimedtoinvestigatethe

3、effectsofUVRCO2aswellastheirinteractiveimpactsonthephotosynthesisgrowthofthemarinediatomNitzschiaclosteriumf.minutissima.Themainresultsareasfollows:UVRledtoanincreaseonROSintheNitzschiaclosteriumf.minutissimacells.Theacc

4、umulatedROSacceleratedtheoxidationofcellmembrane(withanincreasedproductionofmalondialchehycheMDA).PARreducedtheeffectivequantumyieldremarkablymuchloweratUVR.SolarUVRalsoinhibitedthephotosynthesisbydamagingPSII.Innmalseaw

5、aterpHcompensationpointofthealgawas10.08theactualphotosyntheticO2evolutionrateswasmuchhigherthanthetheeticalsupplyratesofCO2dissociatedfromthebiocarbonate(unanalyzedconversionofHCO3toCO2).TheK0.5(HCO3)valuedidn’tchangesi

6、gnificantlywithpHchangesduringtheCO2enrichment.UnderalkalineconditionsphotosynthesiswassignificantlyinhibitedbyanextracellularCA(CAext)inhibitatotalCAinhibit.TheseresultsindicatedthatthisalgaoperateactiveCO2concentrating

7、mechanism(CCM)thattakeupbothCO2bicarbonate.EnrichedCO2concentration(800ppm)downregulatedcarbonconcentratingmechanism(CCM)significantlybuthadnoeffectongrowthratecomparedwithlowCO2level.HighCO2concentrationbroughtaboutlowe

8、rpHthreatenphysiologyofcellsincreaseddarkrespirationreducedelectrontransferrategrowthrate.UnderoutdohigherirradiancelevelstheeffectivequantumyielddeclinedremarkablyduringdaymuchloweratreducedlevelsofpHcausedbytheCO2enric

9、hment.UVRreducedelectrontransferratebetweenphotosystemIIIunderbothlowhighCO2levelbuthavedifferentialeffectsongrowth.HighCO2reducedtheinhibityeffectsofUVRongrowth.EnrichedCO2didn’tenhancethegrowthrateofNitzschiaclosterium