镁对大豆叶片抗氧化代谢的影响

以大豆品种浙春2号、浙春3号和9703为材料,采用土培实验方法,设置不同的镁离子处理水平,研究五 叶期和盛花期大豆叶片叶绿素含量、脯氨酸( Pro)含量、丙二醛(MDA)含量、质膜透性(MP)和抗氧化酶( SOD、POD 和CAT)活性的变化。结果表明,大豆叶片叶绿素含量在五叶期时与镁离子浓度成正相关,盛花期时与镁离子浓度 负相关;在缺镁(0. 00mg/kg)条件下,大豆叶片的脯氨酸含量、MDA含量、质膜透性、超氧化物歧化酶( SOD)和过氧 化物酶( POD)活性较其它处理高,过氧化氢酶(CAT)活性较低;施镁则能显著降低大豆叶片的脯氨酸含量、MDA 含量和质膜透性,其中镁离子浓度60. 00mg/L的效果最好。3个大豆品种五叶期时脯氨酸和MDA含量较对照(0. 00mg/kg)降低1. 38%～22. 96%和12. 60%～44. 50% ,盛花期时则下降了11. 11% ～57. 90%和9. 87% ～71. 61%; 质膜透性五叶期时较对照下降了7. 19% ～38. 61% ,盛花期时则降低了21. 79%～46. 10%。SOD、POD和CAT对镁 的反应存在明显的不同。大豆品种对镁的反应存在一定的基因型差异,浙春3号对镁最为敏感,浙春2号次之, 9703对镁不太敏感。

Effect of magnesium(Mg) on antioxidant metabolism of soybean leaves

Three pot-grown soybean varieties(Zhechun No.2,Zhechun No.3 and 9703) were used to study the effect of Mg on antioxidant metabolism of soybean leaves with different supplementation of magnesium concentration at 5trifoliate and full flowering stages in soil.At 5-trifoliate stage,with the increasing of Mg concentration,the chlorophyll content of soybean leaves increased.While at full flowering,the chlorophyll content of soybean leaves decreased with the increase of Mg concentration.The control plants(0.00mg/kg) exhibited an increase of proline,malondialdehyde(MDA),membrane permeability(MP) and superoxide dismutase(SOD),peroxidase(POD) activities and a decrease of catalase(CAT) activity.With the increase of Mg concentration,the proline content,the cell membrane permeability and MDA content in soybean reduced obviously;while the activities of SOD and POD decreased quickly,and the activity of CAT increased frist and decreased afterwards.So application of Mg raised the ability of antioxidant metabolism of soybean leaves.The effect of medium concentration((60.00mg/kg)) of Mg was the best.At 5-trifoliate stage,the proline and MDA contents of three soybean varieties were 1.38%~22.96% and 12.60%~44.50% lower than the control treatment(0.00mg/kg),11.11%~(57.90%) and 9.87%~71.61% lower than the control at full flowering.The cell membrane permeability was(7.19%)~38.61% lower than the control treatment at 5-foliate stage and 21.79%~46.10% lower than the control treatment at full flowering.There was an obvious difference among reaction of SOD,POD and CAT to Mg.There was also an obvious genetic variation in terms of the response to Mg.Of the three soybean varieties,Zhechun No.3 is sensitive to Mg and showed a weak resistance to the stress of Mg,but its resistance is the highest when application of Mg.The 9703 is less sensistive to Mg.The case of Zhechun No.2 is between Zhechun No.3 and 9703.