Cd2+胁迫对小麦幼苗生长及呼吸作用的影响

以小麦品种郑州9023为材料,研究了不同浓度Cd2 胁迫对小麦幼苗生长及呼吸作用的影响.结果显示:(1)随Cd2 胁迫浓度的升高,小麦幼苗根和芽的呼吸速率及琥珀酸脱氢酶(SDH)活性均呈先上升后下降的趋势.(2)Cd2 胁迫对小麦幼苗根中细胞色素氧化酶(COD)、苹果酸脱氢酶(MDH)、异柠檬酸脱氢酶(IDH)同工酶表达的影响较小,都呈低浓度诱导、高浓度抑制的效应,且Cd2 处理诱导了根中新的MDH、IDH同工酶带的表达;而不同浓度Cd2 对小麦幼苗芽中COD、MDH、IDH同工酶的表达影响较小.(3)随Cd2 胁迫浓度的增加,芽长、根长、芽干重、根干重均呈持续下降的趋势,且对根的抑制作用明显大于对芽.研究表明,Cd2 胁迫可以改变小麦幼苗根和芽中SDH、COD、MDHI、DH等呼吸作用关键酶的活性或同工酶表达,从而影响其呼吸作用,最终抑制了幼苗的生长.

Effects of Cd2+ Stress on Growth and Respiration of Wheat Seedling

Effects of different Cd2 concentration on growth and respiration of wheat seedling were studied with wheat cultivar 'Zhengzhou 9023' as material.The results showed that:(1) respiratory rate and succinate dehydrogenase(SDH) activities in plumule and root of wheat seedling rose at first and then dropped gradually with the increase of the Cd2 concentration.(2)Cd2 was capable of influencing the expression of cytochrome oxidase(COD),malate dehydrogenase(MDH) and isocitrate dehydrogenase(IDH) isoenzymes in root of wheat seedling obviously.They were induced at lower Cd2 concentration,but inhibited at higher concentration.Besides,the expression of new MDH,IDH isoenzymes bands in root of wheat seedling were induced at higher Cd2 concentration;There were no obvious effects to the expression of COD,MDH,IDH isoenzymes bands in plumule of wheat seedling with Cd2 stress.(3) Length and dry weight of root and plumule of wheat seedling all dropped gradually with the increase of the Cd2 concentration.The root was more strongly inhibited by Cd2 than the plumule,which indicated that the root was more sensitive to Cd2 stress.In a word,the heavy metals could change the activity or expression of pivotal enzymes in the respiratory process such as SDH,COD,IDH,MDH isoenzymes,thus influenced respiration of wheat,and further affected the syntheses of substances and energy and resulted in morphological changes of the plants eventually.