Objective To investigate the effects of pulsed electric field on the photosynthetic electron transport and ability to release negative air ions (NAIs) of Agave americana were investigated.
Method Chlorophyll content, rapid chlorophyll fluorescence kinetic functions (OJIP curve), chlorophyll fluorescence parameters, and NAI concentration of A. americana var. Marginata exposed to a pulsed electric field at 0 kV (CK), 5 kV (T1), or 7 kV (T2) were determined.
Result (1) T1 and T2 significantly increased the chlorophyll content over CK by 6.30% and 6.70%, respectively. (2) The OJIP curves had higher deflection (I) and peak (P) than the origin (O) and inflection point (J), a flatter upward trend on I-P than on O-J, and a greater than 0 J-band with the peak of T2 higher than that of T1. (3) T1 and T2 also caused the chlorophyll fluorescence parameters to generally rise on the peak fluorescence intensity (Fm) and energy captured by unit reaction center (TRo/CSo), fall on the PSⅡ light, system potential activity (Fv/Fo), and number of electron transmitters on PSⅡ acceptor side (Sm), and maintain a stable maximum light quantum efficiency (Fv/Fm) as well as fluorescence at J-step (Vj). The performance index based on light energy absorption (PIabs) decreased with an 18.60% reduction by T1 and 14.1% by T2. The comprehensive performance parameter (PItotal) under CK was greater than that under T1 or T2. (4) After a 4h treatment, the NAI concentration increased 87.60% under T1 and 62.09% under T2 from an hour previously. And, during that time, the concentrations differed significantly between T1 and T2, as well as in comparison with CK.
Conclusion Exposure to a pulsed electric field significantly affected the photosynthetic electron transport and NAIs releasing of A. americana. The findings disclosed a means to identify potentially applicable germplasms and a physical treatment to enrich the unique biological function of the plant.
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