极低频高压脉冲电场提高陈年棉种活力的参数优化

Parameter optimization on improving aged cotton seeds vigor by extremely low frequency high voltage pulsed electric field

为研究极低频脉冲电场对陈年棉种活力的影响,该文利用高压脉冲电源和弧形电极-平板组成的电场系统在极间距离为50 mm条件下,以16 k V、10 Hz为中心点,利用Design-expert软件设计正交试验,高压脉冲电场处理棉种时间为40 s。并利用响应面分析法,对发芽势、发芽率、发芽指数、活力指数等4个指标进行参数优化,得出最优处理电压为16.25 k V,最优频率为10.90 Hz。在此基础上,对优化条件进行了试验验证。结果表明:陈年棉种在脉冲电压16.25 k V、脉冲频率10.90 Hz处理条件下,与对照相比,发芽势提高了44.2%,发芽率提高了56.8%,发芽指数提高了64.3%,活力指数提高了81.8%,各指标都达到极显著差异(P<0.01)。陈年棉种的电场生物学效应对电场电压和频率都具有选择性,在电压为16.25 k V、频率为10.90 Hz的脉冲电场作用下,陈年棉种的电场生物学效应最明显,研究结果为后续作物种子高压电场处理的参数优化提供参考。

In order to explore the effect of extremely low frequency high-voltage pulsed electric field on the aged cotton seed vigor, high voltage pulse power supply and arc electrode were used to treat aged cotton seeds with different voltages and frequencies. The treatment time was 40 s. The experiment environment temperature was set as 25 , the relative humidity was ℃set as 30%, and the temperature and humidity were remained relatively stable during the experiment. The effect of high voltage and extremely low frequency on germination ability of aged cotton seeds was studied. The voltage of vertically downward electric field was 12-20 kV, the pulse frequency was 5-15 Hz, the electrode was arc, and the distance between electrode plates was 50 mm. The point of 16 kV and 10 Hz was selected as the center point, and the orthogonal test was designed by Design-Expert software. The CK stood for the aged cotton seeds that had not been treated by electric field. The aged cotton seeds treated by electric field were taken into the sealed bag in time, and all the seeds were germinated within 4 h after treatment. The aged cotton seeds in sealed bag were put separately into the HgCl2 solution with mass fraction of 0.2% for sterilization before seeds germination, and then 50 seeds were selected randomly from each seed sterilization group. Finally, the selected seeds were cleaned and put on the germination bed with sand bed method. The seed germination experiments were carried out at the National Key Laboratory of Crop Biology, Shandong Agricultural University, which were in accordance with the national standard： 25 constant temperature, continuous light, and relative humidi ℃ ty of 100%. Four boxes of seeds were treated under each electric field for 40 s, which were 4 repetitions, and then the average of each index was calculated. During the cotton seeds germination, the moldy cotton seeds should be removed timely, in order not to affect other seeds growth. According to the response surface analysis of the pulsed electric field and the arc electrode to the dynamic index of the aged cotton seed, and the single factor analysis of the pulsed electric field and the arc electrode to the cotton vigor index, the effect of increasing the voltage on the aged cotton seed vigor index was similar. At different voltages, the influence of increasing frequency on the cotton seed vigor index was similar. On the whole, the cotton seed vigor index after arc electrode electric field treatment showed a tendency of rising firstly and then falling with the increasing of voltage and frequency. And the influence of pulse frequency on cotton vigor index was obvious. Using the Design-Expert software, the pulse voltage and frequency were optimized, and the optimal condition was that the pulse voltage was 16.25 kV and the pulse frequency was 10.90 Hz. Under the optimal condition, the germination potential was increased by 44.2%, the germination rate was increased by 56.8%, the germination index was increased by 64.3%, and the vigor index was increased by 81.8%, and the indices were all significantly different （P〈0.01） from that of the CK.