CAJ | 학술논문

采用相同的分离技术,从水葫芦(Eichhornia crassipes(Mart)Solms.)和菠菜(Spinacia oleracea L.)叶片中提取叶绿体.利用吸收光谱和低温荧光光谱及皮秒荧光单光子计数技术对它们的光谱性质和光系统Ⅱ荧光寿命进行了研究.这两种叶绿体吸收光谱相似,暗示着它们都能高效吸收不同波长的光子.低温荧光光谱显示,水葫芦叶绿体两个光系统之间激发能分配平衡状态差,表明不利于该植物叶绿体高效利用吸收的光子能.采用三指数动力学模型对测定的光系统Ⅱ荧光衰减曲线拟合,水葫芦叶绿体光系统Ⅱ荧光衰减寿命分别是:138,521和1 494 ps;菠菜叶绿体荧光寿命分别是:197,465和1 459ps.并且归属了荧光组分,慢速度荧光衰减是由叶绿素堆积造成的,中等速度荧光衰减源于PSⅡ反应中心重新结合电荷组分,快速度荧光衰减归属于PSⅡ反应中心组分.基于20ps模型计算的水葫芦和菠菜叶绿体PSⅡ反应中心激发能转能效率分别是87%和91%.该结果与转能效率为100%的观点不一致.实验结果支持PSⅡ反应中心电荷分裂20 ps时间常数模型.根据转能效率,水葫芦生长速度不大于菠菜生长速度,但是,水葫芦叶绿体中含有丰富的胡萝卜素成分,其单位质量叶绿体吸收光能大于单位质量菠菜叶绿体吸收的量.实验结果还暗示植物叶绿体体系传能高效,接近于100%.
채용상동적분리기술,종수호호(Eichhornia crassipes(Mart)Solms.)화파채(Spinacia oleracea L.)협편중제취협록체.이용흡수광보화저온형광광보급피초형광단광자계수기술대타문적광보성질화광계통Ⅱ형광수명진행료연구.저량충협록체흡수광보상사,암시착타문도능고효흡수불동파장적광자.저온형광광보현시,수호호협록체량개광계통지간격발능분배평형상태차,표명불리우해식물협록체고효이용흡수적광자능.채용삼지수동역학모형대측정적광계통Ⅱ형광쇠감곡선의합,수호호협록체광계통Ⅱ형광쇠감수명분별시:138,521화1 494 ps;파채협록체형광수명분별시:197,465화1 459ps.병차귀속료형광조분,만속도형광쇠감시유협록소퇴적조성적,중등속도형광쇠감원우PSⅡ반응중심중신결합전하조분,쾌속도형광쇠감귀속우PSⅡ반응중심조분.기우20ps모형계산적수호호화파채협록체PSⅡ반응중심격발능전능효솔분별시87%화91%.해결과여전능효솔위100%적관점불일치.실험결과지지PSⅡ반응중심전하분렬20 ps시간상수모형.근거전능효솔,수호호생장속도불대우파채생장속도,단시,수호호협록체중함유봉부적호라복소성분,기단위질량협록체흡수광능대우단위질량파채협록체흡수적량.실험결과환암시식물협록체체계전능고효,접근우100%.
The authors have studied the spectroscopic characteristics and the fluorescence lifetime for thechloroplasts from spinach (Spinacia oleracea L.) and water hyacinth (Eichhornia crassipes (Mart) Solms.)plant leaves by absorption spectra, low temperature steady-state fluorescence spectroscopy and single photoncounting measurement under the same conditions. The absorption spectra at room temperature for the spinachand water hyacinth chloroplasts are similar, which show that different plants can efficiently absorb light of samewavelength. The low temperature steady-state fluorescence spectroscopy for the water hyacinth chloroplast re-veals a poor balance of photon quantum between two photosystems. The fluorescence decays in PS Ⅱ measuredat the natural QA state for the chloroplasts have been fitted by a three-exponential kinetic model. The slow life-time fluorescence component is assigned to a collection of associated light harvesting Chl a/b proteins, the fastlifetime component to the reaction center of PS Ⅱ and the middle lifetime component to the delay fluorescenceof recombination of P+680 and Pheo- . The excited energy conversion efficiency (η) in PS Ⅱ RC is 87% and91% respectively for the water hyacinth and spinach chloroplasts calculated on the 20 ps model. This interest-ing result is not consistent with what is assumed that the efficiency is 100% in PS Ⅱ RC. The results in thispaper also present a support for the 20 ps electron transfer time constant in PS Ⅱ RC. On the viewpoint ofexcitation energy conversion efficiency, the growing rate for the water hyacinth plan is smaller than that for thespinach plant. But, authors' results show those plants can perform highly efficient transfer of photo-excitationenergy from the light-harvesting pigment system to the reaction center (approximately 100%).