小金海棠、番茄和葡萄缺铁应答反应调控机制的比较研究

Comparison of Mechanisms for Regulating Iron Deficiency-adaptive Responses Among Horticultural Crops of Malus,Lycopersicon and Vitis Plants

选取了3种铁高效园艺作物,木本小金海棠,藤本葡萄‘SO4’,草本番茄‘合作906’,对其缺铁应答反应机制进行了分析和比较。结果发现,3种植物中缺铁处理都可以诱导Fe3+还原酶活性升高及根际pH下降;但在缺铁加去顶双重处理时,除番茄Fe3+还原酶活性升高和根际pH下降外,苹果和葡萄没有变化,说明苹果和葡萄中缺铁应答反应的调控有赖于地上部系统信号的存在,而番茄中根系局部信号至少能够触发缺铁应答反应。分根处理表明,在苹果和番茄中部分根系缺铁可导致非缺铁根系产生缺铁应答反应,而葡萄中没有缺铁应答反应,说明苹果和番茄中系统信号可以诱发缺铁应答反应,而葡萄可能需要系统信号和根系局部信号的共同作用。研究还发现,缺铁可诱导苹果和番茄根毛的形成,葡萄则没有。以上结果表明,不同的物种缺铁应答反应的调控机制可能不同。

Various responses to iron deficiency stress were studied in three iron-efficient horticultural crops,Malus xiaojinensis（woody plant）,SO4（vine plant,Vitis）,Hezuo 906（herb plant,Solanum lycopercicum）. The results showed that iron deficiency could induce both higher ferric-chelate reductase （FCR）activity and lower rhizosphere pH in all the three species. However,by shoot tip removal and Fe deficiency treatment,Hezuo 906 showed a higher FCR activity and a lower rhizosphere pH,while both M. xiaojinensis and SO4 remained at the normal iron level,which suggested that the iron deficiency responses in M. xiaojinensis and SO4 relied on the shoot signal,while the sole root local signal could trigger the responses in Hezuo 906. In split-root experiments of the root system with Fe supply developed some Fe efficiency responses in M. xiaojinensis and Hezuo 906,but not in SO4,showing that the shoot signal in M. xiaojinensis and Hezuo 906 could initiate the response to iron stress,while both the shoot signal and the root local signal were required in SO4. Furthermore,the results exhibited that the root hair formation was induced in M. xiaojinensis and Hezuo 906. The different species of horticultural crops may have various regulating mechanisms to iron stress.