铈对酸雨和镉双重胁迫下小麦生理指标的影响

Effect of Cerium on the Wheat Physiological Indices under Coordinated Stress of Acid Rain and Cadmium

以小麦永良4号(Triticum aestivum)为材料,通过营养液水培实验,研究了在酸雨和镉的双重胁迫下,铈对小麦幼苗叶片内丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、硝酸还原酶(NR)活性的影响。实验结果显示:pH2.0+10mg·L-1Cd2+、pH2.0+50mg·L-1Cd2+、pH2.0+200mg·L-1Cd2+三种处理都可明显增加MDA含量,提高SOD活性,降低NR活性,双重胁迫的抑制作用明显,且随着Cd2+的质量浓度增加,抑制程度加重;叶面喷施40mg·L-1的铈预处理后,MDA含量下降,SOD活性降低,NR活性上升,显示叶面喷施适当质量浓度铈可以有效降低小麦体内氧自由基含量,减轻膜系统的损伤,提高小麦对氮肥的利用能力,缓解镉和酸雨双重胁迫对小麦幼苗生长与代谢的损伤。数据还显示:适当铈对三个测定指标的修复作用不同,表现为SOD>MDA>NR。

Hydroponic culture experiment was performed on Triticum aestivum to investigate the effect of Cerium on the malonydialdehyde （MDA） content,superoxide dismutase （SOD） and Nitrate Reductase（NR） activity in the leaves of wheat seedlings under stress of acid rain and Cadmium. The result indicated that treatment with Cd^2＋ solution at 3 different concentrations（pH2.0＋10 mg·L^-1 Cd^2＋,pH2.0＋50 mg·L^-1 Cd^2＋,pH2.0＋200 mg·L^-1 Cd^2＋） invariably lead to significant inhibition by increasing MDA content and SOD activity while reducing NR activity. The inhibition effect improved with increased Cd^2＋ concentration. When 40 mg·L^-1 Ce2＋ was sprayed on leaves under stress,MDA content and SOD activity reduced while the NR activity increased. This indicated that treatment with Ce2＋ at appropriate concentration could effectively eliminate free radicals in the wheat,alleviate the damage on the membrane system,improve the utilization of nitrogen fertilizer,as well as minimize the damage of stress on growth and metabolism of wheat seedlings. It＇s also indicated that Cerium exhibits different repairing ability on 3 indices as follows：SOD〉MDA〉NR.