锌对汞胁迫下小麦种子萌发的影响

通过溶液培养研究了不同浓度锌(Zn)对汞(Hg)胁迫下小麦种子萌发率、芽长、根长以及萌发过程中α淀粉酶、蛋白酶、过氧化氢酶活性的影响。结果表明,单独Hg(15mg·L-1)胁迫下,小麦种子萌发率降低,根长与芽长受到抑制,α淀粉酶与过氧化氢酶活性降低,蛋白酶活性升高。加入10~100mg·L-1Zn后,种子萌发率未表现出明显变化,根长、芽长及α淀粉酶受抑制情况缓解,缓解程度随Zn浓度升高而下降,表明Zn可在一定程度上缓解Hg对小麦种子的毒害,但须在一定浓度范围内;10mg·L-1Zn减弱了Hg单独胁迫对小麦种子蛋白酶活性的促进作用,使其恢复至接近对照水平,20~100mg·L-1Zn则表现出对蛋白酶的抑制作用,使其活性低于对照水平,并且随Zn浓度升高呈下降趋势。Zn的加入对Hg单独胁迫下活性降低的过氧化氢酶未表现出缓解抑制的作用,反而进一步抑制了酶的活性,并且随着Zn浓度升高,抑制作用逐渐加强。因此,Zn的加入可在总体上缓解Hg胁迫对小麦种子萌发的影响,最适Zn浓度为10mg·L-1,但这种缓解作用只表现在部分方面。

Effects of Zn on Seed Germination of Wheat Under Hg Stress

The effects of Zn(10~100 mg·L-1) on the wheat seed germination rate, length of bud and root, activity of α-amylase, protease and catalase in the presence of Hg(15 mg·L-1) were investigated in this study. The results showed that the single treatment of Hg(15 mg·L-1) inhibited the wheat seed germination rate, the root and bud length and the activity of α amylase and catalase, while enhanced the protease activity. The addition of Zn(10~100 mg·L-1) rarely affected the seed germination rate, while reduced the suppression of root length, bud length and α amylase compared to the single treatment of Hg. This remission decreased with the increase of Zn concentration. Which indicated that a certain range of Zn could mitigate the toxicity produced by Hg on wheat seeds. 10 mg·L-1 Zn weakened the promoting function of protease activity by single Hg stress on wheat seeds and almost made it go back to the control level. However, 20~100 mg·L-1 Zn showed an inhibitory effect on the protease, which was lower than the control level, and the influence decreased with the increase of Zn concentration. The addition of Zn enhanced the inhibition of catalase activity caused by single Hg stress.