DOES IRON-DEFICIENCY IN PISUM-SATIVUM ENHANCE THE ACTIVITY OF THE ROOT PLASMALEMMA IRON TRANSPORT PROTEIN
DOES IRON-DEFICIENCY IN PISUM-SATIVUM ENHANCE THE ACTIVITY OF THE ROOT PLASMALEMMA IRON TRANSPORT PROTEIN
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DOI：
10.1104/pp.94.3.1353
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发表时间：
1990-11-01
期刊：
影响因子：
7.4
通讯作者：
KOCHIAN, LV
中科院分区：
文献类型：
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作者：
GRUSAK, MA;WELCH, RM;KOCHIAN, LV
以富铁和缺铁豌豆（Pisum sativumL.）研究了缺铁对水稻根细胞质膜Fe ~（2+）转运蛋白活性的影响。使用Fe（III）-乙二胺四乙酸（Fe[III]-EDTA）在切除的初级侧根中依次测定Fe（III）还原率和短期Fe 2+内流率。由于用于膜运输的细胞外Fe 2+是由根Fe（III）还原产生的，因此根据Fe（III）还原活性对每个根系的Fe 2+流入速率进行归一化。Fe 2+流入的比例Fe（III）的减少（微摩尔Fe 2+吸收/微摩尔Fe[III]减少）显示没有增强的Fe 2+运输能力的铁缺乏豌豆（从亲本基因型，火花）或功能性缺铁豌豆突变体，E107（来自火花），相对于铁充足的火花植物的根。来自使用30至100微摩尔Fe（III）-EDTA的研究的数据表明Fe 2+流入和Fe（III）还原（Fe 2+生成）之间的线性关系，而Fe 2+流入在较高浓度的Fe（III）-EDTA下饱和。根据目前的数据估计，铁离子转运蛋白可能在10− 4.8至10− 4摩尔的铁离子浓度范围内饱和。这些结果意味着，豌豆，生理速率限制铁收购在大多数良好通气的土壤将根系的能力，以减少可溶性铁（III）化合物。
Roots of Fe-sufficient and Fe-Deficient pea (Pisum sativumL.) were studied to determine the effect of Fe-deficiency on the activity of the root-cell plasmalemma Fe2+transport protein. Rates of Fe(III) reduction and short-term Fe2+influx were sequentially determined in excised primary lateral roots using Fe(III)-ethylene-diaminetetraacetic acid (Fe[III]-EDTA). Since the extracellular Fe2+for membrane transport was generated by root Fe(III) reduction, rates of Fe2+influx for each root system were normalized on the basis of Fe(III) reducing activity. Ratios of Fe2+influx to Fe(III) reduction (micromole Fe2+absorbed/micromole Fe[III] reduced) revealed no enhanced Fe2+transport capacity in roots of Fe-deficient peas (from the parental genotype, Sparkle) or the functional Fe-deficiency pea mutant, E107 (derived from Sparkle), relative to roots of Fe-sufficient Sparkle plants. Data from studies using 30 to 100 micromolar Fe(III)-EDTA indicated a linear relationship between Fe2+influx and Fe(III) reduction (Fe2+generation), while Fe2+influx saturated at higher concentrations of Fe(III)-EDTA. Estimations based on current data suggest the Fe2+transport protein may saturate in the range of 10−4.8to 10−4molar Fe2+. These results imply that for peas, the physiological rate limitation to Fe acquisition in most well-aerated soils would be the root system's ability to reduce soluble Fe(III)-compounds.