摘要
ByHPLCanalyticalmethod ,thechangeofPSⅡRC’spigmentcontentintheprocessofphoto damageunderstrongilluminationfromspinach (SpinaciaoleraceaMill.)wascomparativelystudied .Theex perimentalresultsshowthat :(1)Inauthors’analyticalconditions ,(ofwhich ,[Chl]=150 μg/mL ,andthe illuminationstrengthwasputat 2 .3× 10 6 mJ·m- 2 ·s- 1) ,4 5minofilluminationcouldcausealmostthewhole lossofA6 80inthefourthderivativeabsorptionspectra ,whileA6 70decreasedtoaboutonehalfofitsoriginal intensity ;theabsorptionmaximuminred ,concurrently ,wasshiftedfrom 6 76nmto 6 71nm ,representingthe lossofmorethan 90 %ofthephotochemicalactivitiesofthePSⅡRC .(2 )Duringtheperiodofcontinuousil lumination ,theChlconcentrationdecreasedina 3_periodstyle ,whichmeantthatthefirst [Chl]decreasedto the 2 / 3ofitsoriginalamountfrom 2 0minto 4 0minafterilluminationhadstarted ,thenbecamestabilizedup toabout 6 0minofillumination ,thereafteraseconddecreaseof [Chl]inanotherabout2 0minuntilitreached about 30 %oftheoriginallevelandremainedunchangedfromabout 80minon .Theoriginalpigmentcompo nentsofD1/D2 /Cytb559wasapproximatelyas 6Chla∶2Pheo∶2 β_Carwhichareinsupportofauthors’pre viousproposalabouttheminimumChl/Pheoratioof 4∶2inPSⅡRC’spigmentcontents .(3)Afterabout 4 0 minofillumination ,anewlyappearedelutionpeakwasfoundbetweenthePheoandβ_CarpeaksinHPLCpro file ,attheretentiontimeof7.2min ,alittlelaterthanthat (6 .9min)ofPheomolecules ,thenewlyappeared elutionpeakwassupposedtobeakindofaccumulatedandstableproductofthePSⅡRC’sphotodamagepro cessandverymuchpossiblethePheo_likemolecules .
采用高效液相色谱 (HPLC)的分析方法 ,对菠菜 (SpinaciaoleraceaMill.)叶绿体PSⅡ反应中心光破坏过程进行了研究。结果表明 :(1)在本实验条件下 ,45min的光照处理 ,可以使PSⅡ反应中心的光化学活性基本接近丢失。(2 )从光照约 2 0min开始至约 40min ,Chla的含量逐渐减少到原有含量的 2 /3左右 ,然后浓度保持不变至约 6 0min ,此后 ,Chla的含量出现了第二次下降 ,到 80min左右 ,稳定在约 30 %的含量水平并不再变化。D1/D2 /Cytb5 5 9复合物的原有色素分子组成约为 6Chla∶2Pheo∶2 β_Car。 (3)在 40min的光照处理后 ,HPLC图谱上出现了一个新的产物峰 ,其吸收谱十分类似于Pheo分子 (峰位分别为 40 7、5 0 4、5 33、6 0 6及 6 6 3nm) ,但其保留时间 (7.2min)比正常的Pheo分子 (6 .9min)较晚 。
基金
SupportedbytheNationalNaturalScienceFoundationMajorResearchProgram (No .3 9890 3 90 )andpresentlyassistedbytheNationalKeyBasicRe
