铀胁迫对大豆和玉米种子萌发和幼苗生长及SOD与POD活性的影响

采用实验室光照培养箱培养方法,对铀溶液胁迫下大豆和玉米种子的萌发、幼苗的早期生长和幼苗中的超氧化物歧化酶（SOD）、过氧化物酶（POD）活性的变化进行了研究。结果表明,根长较其他指标对铀生态毒性试验更为敏感。与对照相比,在铀浓度为100～1000μmol·L-1的铀溶液胁迫下,大豆种子的萌发率不受影响,芽长受到抑制作用,低浓度的铀溶液对大豆根长有促进作用,高浓度的铀溶液抑制主根生长、但促进生根率,大豆的芽重、根重与对照相比均无显著性差异;胁迫不影响玉米种子的萌发率,但抑制其萌发势、生根势和生根率,低浓度的铀溶液对玉米的根长和根重有促进作用。大豆SOD活性在低浓度时被促进,高浓度时被抑制,POD活性在铀浓度为100μmol·L-1的铀溶液胁迫下即被抑制,且作用随铀浓度的升高而加强;玉米SOD、POD活性先升高后降低,但均高于对照。表明玉米抗铀胁迫的能力强于大豆。

Response of Seed Germination and Seedling Growth and SOD and POD During Seeds of Bean and Corn Germination on Uranium Stress

In recent decades,interest in detailed knowledge of the toxic effects of heavy metals,product of pollution,on plant growth and metabolism has grown.This information is needed for management of crops exposed to pollutants.Uranium can be present in wastewater used for irrigation,and sewage sludge is applied on agricultural soils as phosphorus fertilizer.In this paper,treatments applied in a germination test were 0,100,200,400,600,800,1 000 μmolU·L-1.A germination test was evaluated in 7 days after treatment.Changes in growth and physiological and biochemical factors in day 9 after treatment were recorded.The results showed that the root elongation could be recommended as a sensitive indicator to assess crops ecotoxicity of uranium experiment compares with other targets.For bean,compared the contro（lCK）,all the concentration of uranium showed not affect for germinating rate,the rooting rate protraction at high concentration of uranium,the length of shoot protraction at all concentration of uranium,and the length of root protraction at low concentration of uranium and inhibited at high concentration of uranium,the weight of shoot and root had no significant difference;For corn,all the concentration of uranium showed not affect the germination rate in day 7 after treatment.But limited germination and rooting trend and rooting rate.The length of root,the weight of root were protracted at low concentration of uranium.The activity of SOD of bean in shoot was enhanced under low concentration of uranium and was limited under high uranium concentration;the activity of POD of bean was inhibited with increasing uranium concentration.At the same conditions,The SOD and POD activity of corn were higher than that of check group,and were significantly enhanced especially under low uranium concentration.The experiments revealed that the ability of corn anti-uranium stress strong in soybean.