CAJ | 학술논문

【目的】探讨高温对连翘离体叶圆片光系统Ⅱ活性和叶黄素循环脱环化程度的影响，揭示热胁迫下连翘叶片光合机构的行为特征，充实植物光能高效利用研究领域。【方法】以连翘为供试材料，在功能叶片主叶脉两侧打取直径为1 cm的叶圆片，采用热胁迫温度(26，31，34，37，40，43，46，49和52℃)和时间(5，25和45 min)组合处理，之后于26℃室内环境中暗适应30 min，利用叶绿素成像荧光仪( MINI-IMAGING-PAM)和 QE65光谱仪分别进行叶绿素荧光参数和漫反射率的测定。【结果】在5，25，45 min热胁迫下，连翘叶片 PSⅡ光化学活性 Fv/Fm 和实际光化学量子产量 Y(Ⅱ)开始显著降低的温度分别为43，37，37℃和43，31，31℃。随着热胁迫温度和时间的增加，呈现出暗适应下最小荧光 Fo 和光化学荧光猝灭系数 qP 先减后增的变化、暗适应下最大荧光 Fm 大幅度降低、开放的 PSⅡ反应中心的激发能捕获效率 F'v/F'm和 PSII 电子传输活性 Fm/Fo 迅速降低、调节性能量耗散量子产量 Y ( NPQ)与非调节性能量耗散的量子产量 Y( NO)和值的趋饱和增加、PSⅡ与 PSⅠ间的激发能分配不平衡偏离系数β/α－1先增后降的变化趋势。另外，叶黄素循环脱环化程度负相关的 PRI与 Y( NO)呈现相反变化趋势。【结论】在长时间较高的热胁迫温度下，连翘叶片的热胁迫伤害不仅会发生在PSⅡ蛋白复合体的多个位点，也会发生在整个光合机构，还会从暗反应的酶活性衰减转向 PSⅡ活性衰减；同时，对热胁迫伤害的协调保护机制，一方面表现在过剩的激发能量会从以调节性能量耗散 Y( NPQ)为主转向非调节性能量耗散 Y( NO)为主，另一方面也可能会表现在通过调节 PSⅡ与 PSⅠ之间激发能分配平衡性的天线系统的状态转换上。
【목적】탐토고온대련교리체협원편광계통Ⅱ활성화협황소순배탈배화정도적영향，게시열협박하련교협편광합궤구적행위특정，충실식물광능고효이용연구영역。【방법】이련교위공시재료，재공능협편주협맥량측타취직경위1 cm적협원편，채용열협박온도(26，31，34，37，40，43，46，49화52℃)화시간(5，25화45 min)조합처리，지후우26℃실내배경중암괄응30 min，이용협록소성상형광의( MINI-IMAGING-PAM)화 QE65광보의분별진행협록소형광삼수화만반사솔적측정。【결과】재5，25，45 min열협박하，련교협편 PSⅡ광화학활성 Fv/Fm 화실제광화학양자산량 Y(Ⅱ)개시현저강저적온도분별위43，37，37℃화43，31，31℃。수착열협박온도화시간적증가，정현출암괄응하최소형광 Fo 화광화학형광졸멸계수 qP 선감후증적변화、암괄응하최대형광 Fm 대폭도강저、개방적 PSⅡ반응중심적격발능포획효솔 F'v/F'm화 PSII 전자전수활성 Fm/Fo 신속강저、조절성능량모산양자산량 Y ( NPQ)여비조절성능량모산적양자산량 Y( NO)화치적추포화증가、PSⅡ여 PSⅠ간적격발능분배불평형편리계수β/α－1선증후강적변화추세。령외，협황소순배탈배화정도부상관적 PRI여 Y( NO)정현상반변화추세。【결론】재장시간교고적열협박온도하，련교협편적열협박상해불부회발생재PSⅡ단백복합체적다개위점，야회발생재정개광합궤구，환회종암반응적매활성쇠감전향 PSⅡ활성쇠감；동시，대열협박상해적협조보호궤제，일방면표현재과잉적격발능량회종이조절성능량모산 Y( NPQ)위주전향비조절성능량모산 Y( NO)위주，령일방면야가능회표현재통과조절 PSⅡ여 PSⅠ지간격발능분배평형성적천선계통적상태전환상。
Objective]In this study,we investigated the effects of high temperature on photosystemⅡkinetics activity and de-epoxidation level of xanthophyll cycle components in leaves of Forsythia suspensa to reveal the behavioral characteristics of photosynthetic apparatus under heat stress,and thereby enrich the research field on plant efficient utilization of light energy. [Method]The leaf discs collected from near the midrib of F. suspensa leaves were used as the material and subjected to nine different temperature levels (26 ℃,31 ℃,34 ℃,37 ℃,40 ℃,43 ℃,46 ℃,49 ℃and 52 ℃) with three different treatment time levels (5 min,25 min and 45 min) . After the treatments,the leaf discs were maintained in darkness for 30 minutes at 26 ℃,and then their chlorophyll fluorescence parameters were measured using MINI-IMAGING-PAM system and their diffusing reflectance was tested by QE65 spectrometer,respectively.[Result]The maximal photochemical efficiency (Fv/Fm) obviously decreased at 43 ℃,37 ℃ and 37 ℃,respectively treated for 5min,25min and 45min,while the actual photochemical efficiency (Y(Ⅱ)) decreased steadily,at 43℃, 31℃ and 31℃ under the heat stress time of 5 min,25 min and 45 min. With the increase of treatment temperature and time,the minimum fluorescence of dark adaptation (Fo) and the photochemical fluorescence quenching coefficient (qP) firstly increased and then decreased; The maximum fluorescence of dark adaptation ( Fm ) decreased significantly; The efficiency of excitation energy capture by open PSⅡreaction centers ( F’v/F’m ) and the electronic transport activity of PSII (Fm/Fo) reduced sharply; The sum of the quantum yield of regulated energy dissipation (Y(NPQ)) and the quantum yield of nonregulated energy dissipation ( Y( NO) ) increased with a trend to saturation; The relative deviation from full balance between PSⅡand PSⅠ(β/α-1 ) presented a sudden rise firstly and then sudden drop tendency. However the photochemical reflectance index ( PRI) and Y( NO) showed the opposite trend.[Conclusion]The heat stress not only led to multiple sites injury of PSII protein complexes,but also destroyed the photosynthetic apparatus under a longer-time treatment with higher temperatures condition. In addition,the stress also turned the limiting factor from enzyme activity decay in dark reaction to PSⅡactivity decay. At the same time,the protection mechanisms against heat stress changed from Y( NPQ) to Y( NO) as the main form of energy dissipation,on the other hand,the protection mechanisms might also present by adjusting a balance of excitation energy between PSⅡand PSⅠin the form of state transition of antenna system.