Effect of Pulsed Electric Field on Drought Resistance of Maize Seedling Based on Delayed Fluorescence Induced with LED.

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.