摘要
禾本科植物以大量释放植物高铁载体(phytosiderophores)来增加根际铁的有效性,并通过位于根系质膜上的专一性吸收系统促进植物吸收土壤潜在铁,以适应铁胁迫的不良环境。本研究就诱导植物高铁载体合成和释放因子的专一性、植物高铁载体在石灰性土壤中络合铁的专一性以及植物对 FeⅢ-植物高铁载体络合体吸收的专一性在室内控制条件下作了系统探讨。试验证明,植物高铁载体的合成和释放以及它对石灰性土壤中铁的螯溶作用均非缺铁的专一性反应。缺锌同样可以诱导植物高载体的合成和释放;而植物高载体不仅可以络合石灰性土壤中的铁,同时可以络合其中的锌和铜;它还可能通过氧化还原作用增加石灰性土壤中锰的有效性。另外麦类作物对 Fe^(Ⅲ)植物高铁载体络合体的大量吸收却是缺铁的专一性反应。缺锌和缺锰均不能诱导和活化这一专一性吸收系统。
The specificity of iron acquisition mechanism by graminaceous plants was studied under controlled conditions.The results indicated that the release of phytosideroPhores by wheat is not a specific reaction to iron deficiency. The enhanced release of phytosiderophores was also found by wheat under zinc deficiency.The phytosiderophores were able to mobilize not only iron from Fe~Ⅲ. hydroxide and a calcareous soil,but also zinc,copper and manganese from this soil.The enhanced mobilization of iron,zinc and copper was duc to the chela- tion of phytosiderophores.Whereas the mobilization of manganese might be the result of rduction an insoluble oxide of manganese.O_I_aly the uptake of Fe~Ⅲ-phy- tosiderophores remained a speific reaction to iron deficiency.
关键词
麦类作物
微量元素缺乏
营养
calcareous soil
micronutrient deficiency
mobilization
phytosiderophore
uptake
