重金属镍胁迫对向日葵幼苗生理生化特性的影响

Effects of heavy metal nickel stress on physiological andbiochemical characteristics of Helianthus annuus seedlings

关键词:  向日葵幼苗, 镍胁迫, 生长, 生理生化特性, 响应机制

Key words:  Helianthus annuus seedlings, nickel stress, growth, physiological and biochemical characteristics, response mechanism

摘要:

为揭示向日葵对镍胁迫的响应机制,该文以向日葵幼苗为材料,采用营养液培养法探索了重金属镍胁迫对其生理生化指标的影响。结果表明:低浓度的镍胁迫(≤10 mg·L^-1)有利于幼苗的生长,高浓度的镍胁迫(≥50 mg·L^-1)对幼苗具有明显的抑制作用。随着镍胁迫浓度的逐渐增加,向日葵幼苗各项生理生化指标的变化较大,其中叶绿素、可溶性糖(SS)、可溶性蛋白(SP)、过氧化物酶(POD)活性、游离脯氨酸(Pro)的含量均在1～10 mg·L^-1时呈现上升趋势,在50～100 mg·L^-1时呈下降的趋势,丙二醛(MDA)含量则呈现持续上升趋势。这表明向日葵幼苗对低浓度(1～10 mg·L^-1)镍胁迫能够通过自身调节,增加POD、Pro和MDA等物质的含量来提高对生态环境的抗逆能力,说明向日葵幼苗对重金属镍具有一定抗性; 而高浓度(50～100 mg·L^-1)镍胁迫会破坏其自身防御系统,从而影响幼苗的生长发育。

Abstract:

In order to reveal the response mechanism of Helianthus annuus nickel stress, nutrient solution culture experiments were carried out to probe the affection of heavy metal nickel on physiological and biochemical characteristics by using Helianthus annuus seedlings as materials. The results showed that low nickel concentration(≤10 mg·L^-1)was beneficial to the seedlings growth, and high nickel concentration(≥50 mg·L^-1)had obvious inhibitory effects on seedlings. With the increasing of nickel concentration, the physiological and biochemical indexes changed greatly, in which chlorophyll, soluble sugar(SS), soluble protein(SP), peroxidase(POD)activity, free proline(Pro), all their contents increased when the nickel concentration was 1-10 mg·L^-1, and decreased when the nickel concentration was 50-100 mg·L^-1; but the content of malondialdehyde(MDA)continued to rise. This indicates that the seedlings can used autoregulation to improve resistibility by increasing POD, Pro and MDA in low nickel concentration(1-10 mg·L^-1), and that seedlings have certain resistance to heavy metal nickel, while high concentration(50-100 mg·L^-1)nickel stress will destroy its own defense system so as to affect the growth and development of seedlings.