Cr6+胁迫对小麦幼苗根系生长的影响及DNA损伤效应研究

研究了Cr6+胁迫对3 d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,3 d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;5～20 mg/L Cr6+浓度范围内,3 d龄幼苗根系DNA含量下降幅度大于10 d龄幼苗,Cr6+浓度>20 mg/L时,3 d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;3 d龄幼苗根系DNA增色效应在5～60 mg/L Cr6+浓度范围内大于对照,Cr6+浓度>60 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.

Inhibition of Root Growth and DNA Damage Caused by Cr6+ Stress in Wheat Seedlings

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.