极低频高压脉冲电场对绿豆萌发过程中水分吸收的影响及其机理

Effect of Extremely-low-frequency High-voltage Pulsed Electric Field on Water Absorption of Germinating Mung Beans and Its Mechanism

为研究极低频高压脉冲电场(ELF-PEF)对作物种子萌发过程中水分吸收的影响及其机理,测量了ELF-PEF(电场强度为1 k V/cm、频率为1 Hz、脉宽为80 ms)作用下,萌发绿豆的吸水率、细胞膜相对透性、超氧阴离子自由基()的产生速率及三磷酸腺苷(ATP)含量的变化规律。结果表明:绿豆萌发过程中,吸水率呈现出萌发初期快速吸水、萌发中期缓慢吸水和萌发后期快速吸水的阶段性变化规律;ELF-PEF能够显著提高萌发初期和萌发后期的吸水率,但对萌发中期的吸水率影响不大。分析表明:在绿豆吸涨初期,ELF-PEF通过可逆电穿孔效应增大了细胞膜相对透性,使种子吸水率增大;在萌发中期,ELF-PEF加速了种子的呼吸代谢,产生速率和ATP含量均显著增大;ELF-PEF对萌发后期的细胞膜相对透性影响不大,推测其可能是通过激活细胞膜上的水通道蛋白来促进绿豆萌发后期的吸水作用。

In order to investigate the effect of extremely-low-frequency high-voltage pulsed electric field（ELF-PEF） on germinating crop seeds＇ water absorption and its mechanism, we measured the water absorption rate, relative permeability of cell membrane, production rate of superoxide free radical（O2）, and ATP content of germinating mung beans under ELF-PEF（1 Hz, 1 k V/cm, and pulse width of 80 ms）. The results show that the water absorption of germinating mung beans can be divided into three stages, namely the fast stage, the medium-speed stage and the slow stage corresponding to the initial, the middle and the later periods of the germination. ELF-PEF is significantly effective in promoting the water absorption in the initial and later periods, but rarely in the middle period. It is concluded that, in the initial period of seeds＇ imbibition, ELF-PEF improves the relative permeability of cell membrane through reversible electroporation effect, and thereby increases the water absorption of seeds. In the middle period of germination, ELF-PEF accelerates the respiratory metabolism of seed, and thereby significantly increases the production rate of and ATP content. In the later period, ELF-PEF barely affects the relative permeability of cell membrane, instead may promote water absorption through activating aquaporin in cell membrane.