Cr^(6+)胁迫对小麦幼苗根系生长的影响及DNA损伤效应研究

Inhibition of Root Growth and DNA Damage Caused by Cr^(6+) Stress in Wheat Seedlings

研究了 Cr6 + 胁迫对 3d和 10 d龄小麦幼苗根系生长的影响及 DNA损伤效应 .结果表明 : 1 >5 mg/ L的Cr6 +均显著或极显著降低幼苗根长、根数及根系鲜重、干重 ,3d龄幼苗根系生长比 10 d龄幼苗对 Cr6 +胁迫更敏感 ; 2 所试浓度 Cr6 + 均降低两苗龄幼苗根系 DNA含量 ;5～ 2 0 mg/ L Cr6 + 浓度范围内 ,3d龄幼苗根系 DNA含量下降幅度大于 10 d龄幼苗 ,Cr6 + 浓度 >2 0 m g/ L 时 ,3d龄幼苗根系 DNA含量低于 10 d龄幼苗 ; 3 Cr6 + 对两苗龄幼苗根系 DNA增色效应的影响均呈现随浓度增大先升高后下降的趋势 ;3d龄幼苗根系 DNA增色效应在 5～ 6 0mg/ L Cr6 + 浓度范围内大于对照 ,Cr6 + 浓度 >6 0 mg/ L时则小于对照 ;在所试 Cr6 + 浓度范围内 ,10 d龄幼苗根系DNA增色效应均大于对照 .

The inhibition of root growth and DNA damage resulting from by different concentration of Cr^(6+) were investigated at two growth stages of wheat (Triticum aestivum cv.Xiaoyan No.22) seedlings.The results were as follows:(1) Roots length,roots number,fresh root weight and dry weight of 3-day-old and 10-day-old seedlings all decreased by >5 mg/L Cr^(6+),the root growth of 3-day-old seedlings was more sensitive to Cr^(6+) stress than that of 10-day-old seedlings.(2) The DNA content in root system at two growth stages of seedlings were all reduced by Cr^(6+) concentration;the reduction degree of the DNA content in the root system of 3-day-old seedlings was bigger than that of 10-day-old seedlings in the range of 5~20 (mg/L) Cr^(6+);Cr^(6+)>20 mg/L,the DNA content in the root system of 3-day-old seedling was smaller than that of 10-day-old seedling.(3) With the increase of Cr^(6+) concentration,the effect of Cr^(6+) on hyperchromicity of DNA in the root system at two growth stages of seedlings all firstly increased and then declined;the DNA hyperchromicity in the root system of 3-day-old seedlings was bigger than that of control seedlings in the range 5~60 mg/L Cr^(6+),then was smaller than that of control seedlings in the range of 80~100 mg/L Cr^(6+);the DNA hyperchromicity in the root system of 10-day-old seedlings was elevated by Cr^(6+) concentration.