叶绿素荧光分析技术在野生植物响应多环芳烃（菲）胁迫的应用研究

以叶绿素荧光分析为技术手段，通过研究土壤中多环芳烃（菲）胁迫对野生大豆叶绿素荧光特性以及光能分配参数的影响。结果表明：土壤菲胁迫降低了PSⅡ反应中心活性和电子传递能力，导致其光能利用能力降低。200 mg·kg-1菲胁迫促使F_v/F_m，q_P，ETR和NPQ的发生变化，降低了光合电子传递链上的电子传递能力和光合反应活性；在不同光强的调控下，土壤菲胁迫浓度的增大使得大豆幼苗叶片叶绿素荧光响应曲线Ф_PSⅡ和q_P参数呈现降低趋势，NPQ的上调启动了叶黄素循环途径耗散过剩的辐射激发能，以维持光合机构的正常生理功能。土壤菲胁迫下野生大豆叶片的F_m，F_v/F_m，F_v/Fo和PI_ABS等参数均随着菲含量的增加而降低，即土壤菲胁迫抑制了野生大豆叶片的PSⅡ光化学活性。通过对PSⅡ电子供体侧和受体侧的电子供应及传递能力的研究发现，土壤菲胁迫下野生大豆叶片OJIP曲线上0.3 ms时(即K点)的荧光强度增加，即放氧复合体(OEC)活性降低。土壤菲胁迫还导致OJIP曲线上J点和I点荧光强度的增加，说明土壤菲胁迫导致了野生大豆叶片PSⅡ受体侧电子接受能力的降低，使电子由Q_A向Q_B传递受阻。野生大豆叶片的光能吸收和分配参数也明显受到土壤菲胁迫的影响；随着土壤菲浓度的增加野生大豆叶片PSⅡ反应中心吸收光能用于Q-_A以后的电子传递能量比例和单位反应中心捕获用于电子传递的能量降低，即吸收的光能用于光化学反应的比例降低。因此，土壤菲胁迫下导致PSⅡ电子供体侧OEC的损伤和PSⅡ电子受体侧电子传递能力的降低，以及光能分配利用的改变均是导致其PSⅡ反应中心的活性降低的重要原因。研究结果表明，以叶绿素荧光分析技术可为环境中多环芳烃（菲）胁迫对植物光合作用的影响机理研究提供指导。

Application of Rapid Fluorescence Analysis Technology on Study on Glycine Soja Response to PAHs（Phenanthrene）

In this study, the chlorophyll fluorescence analysis was used as a technical means to study the effects of PAHs (Phe) stress in soil on chlorophyll fluorescence characteristics and light energy distribution parameters of Glycine soja. The results showed that Phe stresses can decrease PSⅡ activity center and the electron transfer ability, resulting in the decrease of the light energy utilization ability, especially for the use of the strong specular ability. Under 200 mg·kg-1 Phe stress conditions, F_v/F_m, q_P, ENR and NPQ were changed, and slow light inhibition occurred in G. soja leaves, which reduced the electron transport capacity and photosynthetic reactivity of the photosynthetic electron transport chain. Under the control of different light intensity and the increase of concentration of Phe stresses that G. soja leaves chlorophyll fluorescence response curve Ф_PSⅡ and q_P parameters showed a trend of decrease, increase of NPQ launched the PSⅡ cycles way excitation energy dissipation of excess radiation, in order to maintain the normal physiological function of photosynthetic institutions. Those parameters such as F_m，F_v/F_m，F_v/F_o and PI_ABS decreased with the increasing concentration of Phe, which means that the soils Phe stressing subdued the photochemical activity of PSⅡ of those G. soja. Based on the study of electronic supply and transmission capacity at electronic donor side and receptor side of the PSⅡ found that on 0.3 ms (K point) of the OJIP curve of Phe stressed G. soja leaf, the fluorescence intensity increased the activity of OEC decreased. Phe stressing also caused the increase of the fluorescence intensityat the J point and I point on the OJIP curve of Phe stressedG. soja leaf. It showed that the Phe stressing reduced the electronically acceptability at the electronic receptor side of PSⅡon the leaves of G. soja, and made the electronic from Q_A to Q_B transfer blocked. The optical energy absorption and distribution parameters of seedling leaves of G. soja were influenced by Phe stressing. With the increase of soil Phe concentration, theratio of optical energy absorbed by PSⅡ reaction center and used for electron transfer after Q-_A and the energy absorbed by each unit reaction center and used for electron transfer was reduced in the leaves of treated G. soja. It means that the proportion of optical energy captured by the reaction center and used for the photochemical reaction was reduced, and the proportion used through the invalid heat dissipation was increased. It could be concluded that there were three important reasons that generated the reduction of activity of PSⅡ reactive center of G. soja leaves under the soil Phe stress, which was the damage of OEC at electron donor side of PSⅡ, the electron transfer ability reducing at the electron acceptor side of PSⅡ and the change of the distribution and utilization of optical energy. This studise on the chlorophyll fluorescence analysis technique could provide guidance for the effect mechanism of plant photosynthesis to PAHs (Phe) stress.