Abstract: Salt stress inhibited crop seed germination, and became the major restriction factor for crops production. In order to explore the mitigative effect of exogenous growth regulators on salt stress and relative mechanism, this paper studied the effect of salt stress on germination of maize seed, and discussed mitigative effect and physiology mechanism of exogenous growth regulator \[γ-aminobutyric acid (GABA), gibberellin (GA3), kinetin (KT), salicylic acid (SA)\] on salt stress taking Xianyu 335 as experimental material. The results showed that: ① the maize seed germination rate decreased, but water uptake rate, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased first and then decreased. All the parameters reached the highest value under 70 mmol/L treatment of salt stress. On the contrary, the contents of malondialdehyde (MDA), soluble protein, soluble sugar and Na+ were gradually increased. ② The exogenous growth regulators could effectively mitigate salt stress and significantly improved seed germination rate, defence enzyme activity, increase contents of K+, Ca2+, Mg2+, and decreased the contents of Na+ and MDA. The exogenous growth regulators could improve salt-tolerant ability of maize, especially GA3 and GABA had performed the optimum effect in mitigating salt stress.

Key words: maize, salt stress, exogenous growth regulator, seed germination, mitigative effect

摘要： 盐胁迫抑制作物种子萌发，成为盐渍化土壤中作物生产的主要限制因子。为探究外源生长调节物质对盐胁迫的缓解效应及相关机理，以先玉335为试验材料，研究了盐胁迫对玉米种子萌发的影响，探讨了外源生长调节物质（γ-氨基丁酸GABA、赤霉素GA3、激动素KT、水杨酸SA）对盐胁迫的缓解效应和生理机制。结果表明：①随盐胁迫加剧，玉米种子的发芽率逐渐降低；吸水速率、超氧化物岐化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）等保护酶活性先增后降，且均在70 mmol/L盐胁迫处理下达到最大值；丙二醛（MDA）、可溶性蛋白、可溶性糖和Na+含量逐渐升高。②外源生长调节物质可有效缓解盐胁迫，显著提高玉米种子的吸水萌发率、保护酶活性，增加渗透调节物质含量及K+、Ca2+、Mg2+离子的含量，降低Na+和MDA的含量。外源生长调节物质可提高玉米的耐盐能力，其中GA3和GABA对盐胁迫的缓解效应最佳。

关键词: 玉米, 盐胁迫, 外源生长调节物质, 种子萌发, 缓解效应