烟草愈伤组织在热胁迫过程中活性氧与抗氰呼吸变化的关系

Relationship Between Active Oxygen Species and the Cyanide resistant Respiration in Tobacco Callus Under Heat Stress

烟草愈伤组织在 0～ 14h高温 (4 0℃ )胁迫期间 ,其体内的O- ·2 和H2 O2 迅速积累 ,分别在 2和 6h左右达到极大值。同时清除它们的酶SOD和CAT活性迅速上升 ,极大值的分布位置分别为 2和 10h左右 ,而胁迫期间的抗氰呼吸比未胁迫 (0h)时显著地下降 ,但在胁迫期间抗氰呼吸于 6h左右出现一峰值 ;用外源H2 O2 和O- ·2 及清除它们的酶的抑制剂AT和DCC分别处理愈伤组织 ,发现抗氰呼吸明显地加强。推测交替氧化酶可能同抗氧化酶如SOD和CAT一样参与了活性氧的清除 ,提出活性氧含量的变化可能是导致热胁迫过程中抗氰呼吸变化的主要原因之一。

The relationship between active oxygen species and the cyanide resistant respiration in tobacco callus under heat stress were investigated. During the 14 h stress period under 40℃, the O -· 2 and H 2O 2 contents increased rapidly and reached their maxima after about 2 h and 6 h stress respectively (Figs.3, 4). At the same time, the activities of SOD and CAT also increased steadily and their respective peaks appeared after about 2 h and 10 h of stress (Figs.5, 6). The cyanide resistant respiration decreased greatly during the process of stress in comparison to control (0 h), but the cyanide resistant respiration decreased[HJ6:2] greatly after 6 h of stress (Fig.1). The same results were obtained when exogenous O -· 2 , H 2O 2, DDC and AT were used (Figs.7, 8). These results suggested that the alternative oxidase might participate in the elimination of active oxygen species in a similar way as SOD and CAT, and that the changes in rate of the cyanide resistant respiration were associated with those in content of the active oxygen species.