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作 者 ：屠洁 沈文飚 叶茂炳 徐朗莱

期 刊 ：植物学通报 2002年 19卷 03期 页码：336-341

关键词：小麦；一氧化氮；过氧化氢；清除酶；抑制；

摘 要 ：分析了外源一氧化氮（nitric oxide ，NO）供体硝普钠（sodium nitroprusside，SNP）对离体小麦（Triticum aestivumL.）叶片过氧化氢（H2O2）含量及其清除酶活力的调节作用。不同浓度的SNP (1 mmol/L和5 mmol/L) 处理30 min内， 离体小麦叶片H2O2含量均有一个显著上升的过程， 同时过氧化物酶（POD） 活力受到显著抑制，而过氧化氢酶（CAT）活力则轻微下降；处理30 min到240 min时，POD活力的抑制状态基本维持不变，而CAT 活力开始恢复上升， H2O2含量也相应地开始下降。粗酶液的体外实验也表明，SNP对POD和CAT的抑制类型不同，前者可能是不可逆抑制，后者则可能是可逆抑制。因此NO可通过对POD和CAT的不同抑制作用来调节小麦叶片内源H2O2含量。

Abstract:The effects of nitric oxide (NO) donor on the changes of hydrogen peroxide （H2O2） content and its scavenging enzymes activities were surveyed in detached leaves of wheat (Triticum aestivum L.). Treatments with different concentrations of sodium nitroprusside (1 mmol/L and 5 mmol/L SNP), a nitric oxide donor in vivo, enhanced H2O2 levels significantly within 30 minutes of incubation. Meanwhile, guaiacol peroxidase (POD) activities were dramatically inhibite d, and the activities of catalase (CAT) displayed slight decrease. However, prolonging the treatment to 240 minutes gradually reduced the content of H2O2, which might be due to the restoration of CAT activities rather than consistent inhibition of POD. In vitro experiments also indicated that the inhibition of wheat POD in crude extracts by varying concentrations of SNP appeared to be irreversible in comparison with the reversible inhibition of CAT. Therefore, NO played a role in regulating H2O2 levels in detached wheat leave in vivoby different inhibiting modes of POD and CAT.

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