镉胁迫对小麦生长发育的影响

Effects of Cadmium Stress on the Growth and Development of Wheat

为探究小麦种子萌发、幼苗生长时期对镉胁迫的耐性及镉毒害机理,以‘周麦22’为试材,采用不同浓度镉胁迫(0、0.04、0.4、0.8、1.2 mmol/L)的无土栽培试验,统计胁迫下种子的发芽势、发芽率、发芽指数和活力指数,测定小麦幼苗形态指标、生物量、MDA、渗透调节物质和保护酶。结果表明:0.4~1.2 mmol/L时,发芽率、发芽势、发芽指数、活力指数、株高、根长、地上部干鲜质量和地下部干鲜质量均随镉浓度的增加而降低。叶片可溶性糖含量呈先略微升高后降低的变化趋势;游离氨基酸、脯氨酸和丙二醛(MDA)含量均随镉胁迫强度的增加而增加,至1.2 mmol/L时分别为对照的2.61、5.20和7.99倍。0.4 mmol/L时SOD、POD和CAT活性最高,而APX活性则在镉浓度0.04mmol/L时最高。总之,高浓度镉对小麦种子萌发和幼苗生长有极显著抑制作用并降低保护酶活性,游离氨基酸、脯氨酸和MDA含量随镉胁迫强度的增加而增加。

To explore the tolerance to cadmium germination and seedling growth of wheat, taking stress and the mechanism of cadmium toxicity during seed Zhoumai22＇ as the test material, the seeds under different cadmium stresses （0, 0.04, 0.4, 0.8, 1.2 mmol/L） were used in the soilless culture experiment. The germination potential, germination rate, germination index and vigor index of the seeds under statistical stress were measured, and the morphological indexes, biomass, MDA, osmotic adjustment substances and protective enzymes of wheat seedlings were measured. The results showed that under the cadmium stress of 0.4-1.2 mmol/L, the germination rate, germination potential, germination index, vigor index, plant height, root length, dry and fresh quality of the aboveground part and the dry and fresh quality of the underground part all decreased with the increase of cadmium concentration. The content of soluble sugar in leaves decreased slightly, and the content of free amino acids, proline and malondialdehyde （MDA） increased with the increase of cadmium stress, and under the cadmium concentration of 1.2 mmol/L, the content was 2.61, 5.20 and 7.99 times as much as that of the control. The activity of SOD, POD and CAT was the highest when cadmium concentration was 0.4mmol/L.while APX activity was the highest when cadmium concentration was 0.04 mmol/L. concentration of cadmium significantly inhibits the seed germination and the activity of protective enzymes. The contents of free amino acids, increase of cadmium stress. seedling growth In conclusion, high of wheat and reduces proline and MDA increase with theincrease of cadmium stress.