外源谷胱甘肽对大豆种子萌发过程中铜毒害的缓解效应

设置0、0.5、1.0、2.0和4.0 mmol.L-1铜离子浓度梯度,同时在各浓度梯度中分别添加0.16和0.32 mmol.L-1的谷胱甘肽(GSH),进行大豆种子萌发试验,通过测定萌发率、相对电导率、脯氨酸含量及α-淀粉酶活性等指标研究了GSH对大豆种子铜胁迫的缓解效应。结果表明:1.0 mmol.L-1以上浓度铜显著降低大豆种子的活力指数及幼根长,显著提高电解质渗透率及脯氨酸含量;2.0 mmol.L-1以上浓度铜离子显著降低大豆种子的发芽指数及α-淀粉酶活性;4.0 mmol.L-1铜离子显著抑制萌发率。添加0.16和0.32 mmol.L-1的GSH能显著提高1.0 mmol.L-1以上浓度铜毒害条件下α-淀粉酶活性,降低脯氨酸含量,增加幼根长,并能显著降低2.0 mmol.L-1以上浓度铜毒害下的电解质渗透率;4.0 mmol.L-1浓度铜毒害条件下,添加0.32 mmol.L-1的GSH能显著提高大豆种子的萌发率、发芽指数和活力指数。综合考虑,0.16和0.32 mmol.L-1的GSH能够通过提高α-淀粉酶活性来增强大豆种子的萌发能力,并通过维持细胞膜完整性来缓解一定浓度的铜胁迫。

Alleviation Effects of Exogenous Glutathione on Copper Toxicity during Soybean Seeds Germination

The alleviation effects of exogenous GSH on copper toxicity during soybean seeds germination was studied in this paper.The soybean seeds were soaked in solution with different copper concentrations of 0,0.5,1.0,2.0,4.0 mmol·L-1,supplied with 0.16 and 0.32 mmol·L-1 GSH,and then the seeds germination rate,relative permeability,proline content and activity of α-amylase were investigated.The results showed that the copper concentration of 1.0 mmol·L-1 or above evidently decreased the activity index and radicle length,but the relative electrolyte permeability and proline content were enhanced remarkably;2.0 mmol·L-1 or above copper concentration notably reduced the germination index and activity of α-amylase;4.0 mmol·L-1 copper observably restrained the germination rate.Under 1.0 mmol·L-1 or above copper stress,0.16 and 0.32 mmol·L-1 GSH markedly improved the activity of α-amylase and radicle length,but reduced proline content.Under 2.0 mmol·L-1 or above copper stress,0.16 and 0.32 mmol·L-1 GSH evidently decreased the relative electrolyte permeability.Under 4.0 mmol·L-1 copper stress,0.32 mmol·L-1 GSH remarkably enhanced the germination rate,germination and activity index.These results indicated that 0.16 and 0.32 mmol·L-1GSH improved the ability of soybean seeds germination via enhancing the activity of α-amylase,meanwhile,alleviated copper toxicity on soybean seeds in a certain extent to maintain the integrity of cell membrane.