Cu^(2+)胁迫对马来眼子菜光合荧光特性的影响

Influence of Cu^(2+) stress on photosynthetic fluorescence characteristics of Potamogeton Malaianus

以马来眼子菜为试验材料,采用5个浓度水平的Cu^(2+)胁迫马来眼子菜,利用水下调制荧光仪测定叶片PSⅡ最大光化光效率Fv/Fm、潜在光化光效率Fv/Fo、有效量子产量Y(Ⅱ)、非调节性能量耗散的量子产额Y(NO)、光化学淬灭系数qP、非光化学淬灭系数q N等光合荧光参数,探讨各参数随Cu^(2+)浓度递增的变化规律。结果表明,马来眼子菜的Fv/Fm、Fv/Fo、Y(Ⅱ)和q P随着Cu^(2+)处理浓度增加呈显著下降趋势;在Cu^(2+)浓度为4.0 mg/L时,分别比对照组降低了81.43%,93.61%、85.3%和24.74%,说明Cu^(2+)对马来眼子菜叶片PSⅡ反应中心的光能吸收、能量转换和电子传递产生严重影响;Y(NO)与Y(Ⅱ)呈相反趋势,q N随处理浓度的增加呈现先增加后降低的趋势,说明Cu^(2+)胁迫下,植物叶片为实现光合自我保护,将叶片吸收的部分光量子以非调节性和调节性能量耗散。

Using Potamogeton Malaianus as the experimental material,five levels of Cu2＋ were used to stress the plants.The maximum actinic light efficiency Fv/Fm,actinic light efficiency Fv/Fo,effective quantum yield Y（II）,unregulated energy dissipation quantum Y（NO）,photochemical quenching coefficient q P,and non-photochemical quenching coefficient q N were measured by a submerged,modulating fluorometer（Diving-pam）.The change rule of various parameters with increasing Cu2＋ concentration was discussed.The results show that Fv/Fm,Fv/Fo,Y（II） and q P present a significant decrease with the increase of Cu2＋.When Cu2＋ was 4.0 mg/L,it was 81.43%,93.61%,85.3% and 24.74% lower than the control group,respectively.It is indicated that Cu2＋ has a serious impact on the light energy absorption,energy conversion and electron transport of the PSII reaction center of the leaves on P.Malaianus.Y（NO） and Y（II） had opposite trends,and q N increased first and then decreased with increasing treatment concentration,which indicates that for self-protection of photosynthesis,some of the photons absorbed by the leaves are dissipated by non-regulatory and regulatory energy under Cu2＋ stress.