低温诱导绿豆黄化幼苗乙烯产生过程中活性氧的作用

The Role of Active Oxygen in Chilling-Induced Ethylene Production in Etiolated Mungbean Seedlings

低温明显诱导绿豆 (PhaseolusradiatusL .)黄化幼苗乙烯产生速率的升高 ,同时也诱导活性氧产生速率不同程度的提高 ,显示二者之间有密切的关系。乙烯合成抑制剂AVG (2 aminoethoxyvinlglycine)、AOA(aminooxyaceticacid)能明显减弱低温对绿豆黄化幼苗乙烯产生的诱导作用 ,但对活性氧的产生没有明显的影响 ,说明低温诱导的乙烯产生的增加并不是活性氧产生增加的原因。超氧阴离子自由基 (O- ·2 )的特异性清除剂SOD和DABCO(1,4 diazabicyclo 2 ,2 ,2 octane)能有效削弱低温对乙烯产生的诱导作用 ,外源O- ·2 产生系统明显促进经过低温处理的幼苗回到常温下生长初期乙烯产生的增加 ,说明O- ·2 产生的增加可能是低温诱导乙烯产生增加的原因之一。低温诱导的H2 O2 产生的增加则被证明与乙烯产生速率的升高没有直接关系。

The production rate of ethylene, as well as that of active oxygen, increased obviously in etiolated mungbean seedlings which grew at 25℃ after 5 h chilling stress at 5℃ in the darkness, showing a close relation between the increase in ethylene production rate and that in active oxygen production (Figs.1, 2). The specific inhibitor of ethylene synthesis, AVG (2-aminoethoxyvinlglycine) and AOA (aminooxyacetic acid), could inhibit the chilling-induced increase in ethylene production, but not that in active oxygen production, indicating it is not through increasing ethylene production that low temperature stress induces an increase in active oxygen production (Fig.3). The specific scavenger of superoxide radical (O -· 2), SOD (superoxide dismutase) and DABCO(1,4-diazabicyclo-2,2,2-octane), could bate the increase of ethylene production in etiolated mungbean seedlings after chilling stress, the exogenous O -· 2 (10 mmol/L methyl viologen or Na 2S 2O 4 ) could promote ethylene production in early growing stage in normal temperature after chilling stress in etiolated seedlings (Fig.4), which demonstrated that the increase in O -· 2 production may be the cause of the increase in ethylene production under chilling stress. The possibility of H 2O 2's mediating the stimulative effect of chilling stress on ethylene production can be excluded (Fig.5).