低浓度镍处理下玉米种子的萌发与活性氧代谢的关系

Relationship between Seed Germination and Active Oxygens Metabolism in Maize Treated with Low Nickel Concentration

采用温室土培盆栽试验 ,研究了 0 5、0 75、1 0和 1 2 5 μmol/L的硝酸镍浸种后玉米种子的萌发 ,并对 0 5和 1 0μmol/L镍处理后萌发过程中抗氧化酶系统活性、O—·2 产生速率、H2 O2 和丙二醛 (MDA)含量、种子外渗液电导率进行了测定。结果表明 ,镍处理明显提高了玉米种子的发芽率、发芽势和活力指数 ,缩短平均发芽日数 ,说明镍对玉米种子的萌发有显著的促进作用。其中以 1 0 μmol/L浓度处理效果最好。同时 ,镍提高了种子萌发时超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)和过氧化物酶 (POD)活性 ,降低了O—·2 产生速率、H2 O2 含量、MDA含量、种子外渗液电导率 ;4条POD同工酶带增强 (Rf=0 2 5 6 ,0 395 ,0 4 89,0 5 5 8)。这些结果提示镍通过提高玉米种子萌发期间的抗氧化水平 ,缓减脂质过氧化作用 ,从而维持种子质膜结构的完整性 ,防止电解质过度流失 ,是其促进种子萌发可能的生理背景。

The effects of nickel (0 5,0 75,1 0,1 25 μmol/L) on the seed germination of maize ( Zea mays L.) and some physiological characteristics such as the generation rate of superoxide radical (O -· 2),the contents of peroxide hydrogen (H 2O 2) and malondialdehyde (MDA),and plasma membrane permeability after treatments with 0 5,1 0 μmol/L nickel,were studied in green house in pot cultivation.The germination of maize seeds was promoted by nickel and its active oxygens metabolism was explored at the same time.The results showed that the germination frequency and index,vigor of the seeds appeared to be increased,and the mean days of germination decreased by nickel treatments.It indicated that nickel accelerated the seed germination,and the positive effect of 1 0 μmol/L nickel was the best.It was also observed that the activity increasing of superoxide dismutase (SOD),catalase (CAT) and peroxidase (POD) was accompanied with the decreasing of the O -· 2 generation rate,H 2O 2 content,MDA content and seed leakage electroconductivity.The result of isozyme PAGE analysis showed that the 4 POD isozyme bands ( R f =0 256,0 395,0 489,0 558) became stronger.It was suggested that the enhancement of antioxidation level and the mitigating of lipid peroxidation by nickel treatments,which were beneficial to the integrity of plasma membrane and electrolytes keeping,might be the physiological basis of the seed germination accelerated by nickel.