镉胁迫对不同小麦品种生理特性及抗氧化酶类活性的影响

Effects of cadmium stress on physiological parameters and antioxidant enzymes activities in different cultivars of wheat

以小麦品种川育12,川麦42,川麦47和小观54-2为材料,生长15 d后用200μmol/L CdCl_2水培小麦幼苗,研究镉(Cd)胁迫对不同品种小麦幼苗抗氧化酶类活性的影响.结果表明,Cd胁迫4 d的情况下,四个小麦品种的抗氧化酶类活性没有受到较大影响,品种间也无明显区别.但在Cd胁迫8 d时,川育12受镉胁迫最为严重,生长最差,丙二醛(MDA)含量明显升高,电导率也大幅度上升,抗氧化酶类活性也受到不同程度的影响,超氧化物歧化物(SOD),过氧化物酶(POD),抗坏血酸过氧化物酶(APX)和谷胱甘肽过氧化物酶(GPX)活性均受到强烈抑制.相反,川麦47和小观54-2两个品种表现出对镉较强的耐受性,Cd胁迫下MDA和电导率都没有明显改变,且保持有较高的绝对含水量,抗氧化酶类活性也随着Cd胁迫时间的加长而受到诱导增强.此外,四个品种均在根部积累了较多的镉离子,叶片中积累很少.镉离子积累量顺序依次是:川育12>川麦42>川麦47>小观54-2.因此可以推测,吸收较多的镉对抗氧化酶类活性形成抑制作用,从而也说明了不同小麦品种对镉的抗性机理的不同.

The effects of cadmium （Cd） stress on the activities of antioxidant enzymes of four wheat （Triticurnaestivurn L. ） cultivars （Chuanyu 12, Chuanmai 42, 47 and Xiaoguan 54-2） were studied. The seedlings were treatmented with 200 μmol/L CdCl2 for 15 days. The results showed no obvious differences among four wheat cultivars during Cd stress for 4 days. After 8 days, however, Chuanyu 12 was worst affected by Cd stress, the growth was also inhibited and malondialdehyde （MDA） content significantly increased as well as the electric conductivity. In Chuanyu 12, superoxide dismutase objects （SOD）, peroxidase （POD）, ascorbate peroxidase （APX） and glutathione peroxidase （GPX） were subjetted to strong inhibition by Gd stress. On the contrary, Ghuanmai 47 and Xiaoguan 54-2 showed a strong tolerance to cadmium. These two cultivars maintained a higher degree of absolute water content, and their MDA and conductivities did not change significantly, while their antioxidant enzyme activities were even enhanced under Cd stress. In addition, four cultivars were accumulated large content of cadmium ions in roots but little in leaves. Cadmium concentrations accumulated in roots was in the order of Chuanyu 12〉Chuanmai 42〉Chuanmai 47〉Xiaoguan 54-2. These results showed that excessive absorption cadmium in root may decrease antioxidant enzyme activities, which also illustrated that the resistance mechanisms are different among the four wheat cultivars.