脉冲电场(pulsed electric field, PEF)对作物抗旱性的影响是电场生物学效应研究的重要课题, 作物叶片延迟荧光动力学参数可以从不同角度灵敏地反映叶片细胞光合系统发生的变化。 为了从活体细胞角度揭示脉冲电场对作物幼苗抗旱性的影响及其机理, 使用频率为1 Hz、 场强为200 kV·m-1、 脉宽为80 ms的PEF处理萌发玉米种子, 再采用渗透势为-0.1 MPa的PEG-6000溶液形成干旱胁迫, 研究了玉米幼苗生长过程中叶片干质量和LED诱导的叶片延迟荧光动力学参数的变化。 结果发现, 在-0.1 MPa的PEG-6000溶液形成的干旱胁迫下, 玉米幼苗叶片干质量逐渐增加, 经过PEF处理的玉米幼苗叶片干质量大于对照, 相对增长率在5.8%～18.7%之间(p＜0.05)。 叶片延迟荧光动力学分析显示, 干旱胁迫下玉米幼苗叶片延迟荧光动力学参数初始光子数I0、 相干时间τ、 衰减参数β和延迟荧光积分强度I(T)都发生了波动性的变化, 这些变化是叶片细胞对干旱胁迫的适应性反应, PEF处理使玉米幼苗叶片延迟荧光各动力学参数和延迟荧光积分强度均明显大于对照组, 表明PEF处理使玉米幼苗叶片细胞的光合潜力、 组织序性和功能分子之间的相互作用都有所加强, 叶片综合光合能力提高了。 研究结果为阐明PEF对作物幼苗抗旱性的影响及其机理提供参考。

Effect of pulsed electric field on the drought resistance of crops is an important topic in biological effect of electric field. The changes in the photosynthetic system of leaf cells can be sensitively reflected by the kinetics parameters of delayed fluorescence. In order to reveal the effect of pulsed electric field and its mechanism on drought resistance of crop seedling, the germinating maize seeds were treated by pulsed electric field with electric field strength 200 kV·m-1, frequency 1Hz and pulse width 80ms. Then, PEG-6000 solution with -0.1 MPa osmotic potential to was used to form physiological drought of maize seedlings, the changes of dry leaf mass and the kinetics parameters, induced by LED were studied in this paper. The result showed that the dry leaf mass gradually increased under drought stress after applied with the electric field, which was significantly higher than that without external field, the relative growth rate was 45.6% (p<0.01). Besides, during the processes, the relative growth rate was between 5.8%～18.7%, the difference was significant (p<0.05) when there was no electric field, which indicated that the pulsed electric field promoted the leaf growth of maize seedling. The analysis of delayed fluorescence kinetic about leaf of maize seedling showed that the value of delayed fluorescence kinetics parameters, initial photon number I0, coherence time τ, decay factor β and integral intensity I(T), under drought stress, showed fluctuation, These changes were response to drought stress made by leaf cells. The study also found that pulsed electric field increased delayed fluorescence kinetics parameters and the integrated intensity of leaf cells, which indicated that the pulsed electric field could improve the photosynthesis potential and the organize sequence of photosynthetic electron transport system in leaf cells, as the interaction between functional molecules was strengthened, the leaf photosynthetic capacity was enhanced under drought stress. The result of this study provides a reference to explain clearly the effect of the pulsed electric field on drought resistance of plants seedlings.