苹果砧木SH40 和八棱海棠缺铁胁迫下根系有机酸分泌的差异

 以苹果砧木SH₄₀和八棱海棠(Malus micromalus) 的生根试管苗为试材, 采用水培方法, 研究了缺铁胁迫对根系分泌有机酸的种类和数量的影响。结果表明: SH40和八棱海棠根系分泌有机酸种类相同,主要是草酸、丙二酸、酒石酸、苹果酸和柠檬酸, 但在分泌总量上差异明显, 八棱海棠分泌有机酸总量大于SH₄₀。缺铁胁迫时SH₄₀草酸分泌量和八棱海棠柠檬酸分泌量大量增加, 且八棱海棠干物质和铁含量明显高于SH₄₀。草酸和柠檬酸分泌量增加可能是SH₄₀和八棱海棠耐受缺铁胁迫的原因之一。

Difference of Organic Acid Exudation from Roots of SH40 and Balenghaitang under Iron-deficiency Stress

SH40 and Balenghaitang(Malus micromalus),apple rootstocks,were used as experimental materials to study the organic acid exudation from roots grown hydroponically under iron-deficiency stress.Results showed no difference in types of organic acids between SH40 and Balenghaitang under iron-deficiency,including oxalate,malonic acid,tartaric acid,citrate acid and malate.The quantity,however,was significantly different.The total amount of organic acid of Balenghaitang,which has higher in iron-deficiency tolerance,was higher than that of SH40.On the other hand,oxalate and citrate exuded from SH40 and Balenghaitang were increased largely under iron-deficiency stress,and dry mass and Fe content of Balenghaitang were significantly higher than that of SH40.In summary,significantly increased oxalate and citrate exudation is probably responsible for the tolerance of SH40 and Balenghaitang to iron-deficiency stress.