不同浓度镉胁迫对冬小麦根系生长的影响

Effects of different cadmium stress on root system of winter wheat

采用营养液培养方法,研究了不同镉浓度处理对小麦根系鲜质量、总根长、根表面积、根体积、根尖数、平均直径及不同直径下总根长、表面积和体积的影响。结果表明,施镉降低了根鲜质量,且在高浓度镉(Cd 50)处理下降低幅度最大,达到23.95%,这说明镉抑制了冬小麦根系生物量的积累。相对于Cd 0处理,Cd 0.5,Cd 5和Cd 50处理总根长分别降低了8.49%,7.34%(P<0.05),14.88%(P<0.05)。这说明镉能够明显抑制冬小麦根系的正常生长和伸长;对不同直径根长和总根长进行相关性分析发现,小麦根长的降低与Ⅰ级(0 cm<根长≤0.5 cm),Ⅱ级(0.5 cm<根长≤1.0 cm)和Ⅷ级(3.5 cm<根长≤4.0 cm)直径间有显著正相关关系。同时,相对于Cd 0处理,Cd 50处理显著降低了小麦根系表面积,降低幅度为12.31%;对不同直径根表面积和总根表面积进行相关性分析发现,表面积的降低与Ⅰ级(0 cm 2<根表面积≤0.5 cm 2)和Ⅱ级(0.5 cm 2<根表面积≤1.0 cm 2)直径间有极显著正相关关系。同样对不同直径根体积和总根体积进行相关性分析发现,根系体积与Ⅱ级(0.5 cm 3<根体积≤1.0 cm 3)直径间有极显著正相关关系。因此,在镉抑制小麦根的形态中,镉抑制细根的生长和形态扮演重要角色。

A hydroponic experiment was carried out to explore the effects of different cadmium(Cd)concentrations of hydroponic system on root growth and morphological traits of wheat.The results showed that the application of Cd reduced the fresh root weight and the maximum reduction reached to 13.95%under the treatment with highest concentration of Cd(50μmol·L^-1,Cd 50),which suggested that Cd inhibited biomass accumulation in wheat root.Compared to control(Cd 0),the Cd 0.5,Cd 5 and Cd 50 treatments reduced root length by 8.49%,7.34%,and 14.88%(P<0.05),respectively.This indicated that Cd could significantly inhibit the growth and elongation of winter wheat roots.The correlation analysis between root length with different diameters and total root length showed a significant positive correlation between the reduction of total root length and the diameter of roots amongⅠ(0 cm<L≤0.5 cm),Ⅱ(0.5 cm<L≤1.0 cm),andⅧ(3.5 cm<L≤4.0 cm).Compared with Cd 0 treatment,Cd 50 treatment significantly reduced the surface area of wheat root by 12.31%.The correlation analysis of total root surface area and root surface area with different diameters showed that the decrease of surface area was positively correlated with the root surface area betweenⅠ(0 cm 2<S≤0.5 cm 2)andⅡ(0.5 cm 2<S≤1.0 cm 2).Meanwhile,the correlation analysis of total root volume and root volume with different diameters showed that the volume was positively correlated with the root volume ofⅡ(0.5 cm 3<V≤1.0 cm 3).Therefore,Cd stress plays an important role in growth and morphology of fine wheat roots inhibition.