United States Department of Agriculture, Agricultural Research Service, SWC, Mineral Nutrition Laboratory, Beltsville, Maryland 20705.
Plant Physiol. 1970 Mar;45(3):280-3. doi: 10.1104/pp.45.3.280.
Soybean plants, Glycine max (L.) Merrill, in standard solution received 2.5 mum ferric ethylenediamine di(o-hydroxyphenylacetate (FeEDDHA) and 0 to 128 mum phosphorus. Their stem exudates contained: 32 to 52 mum Fe, 120 to 5000 mum P, and 120 to 165 mum citrate. Electrophoresis of exudates with high P caused Fe trailing that precluded identification of any major form of Fe. Exudate with low P gave an anodic band of Fe citrate as the major Fe compound. Phosphate added to exudate in vitro depressed the Fe citrate peak and cause Fe trailing. EDDHA added to exudate in vitro pulled Fe from Fe citrate; citrate then migrated as a slower form and Fe migrated as FeEDDHA. A modified preculture system, involving 2-day renewals of 0.2 mum FeEDDHA with 3.2, 9.6, or 16 mum P and low levels of other ions, controlled pH depression and produced considerable change in citrate and P levels. The exudates contained: 45 to 57 mum Fe, 200 to 925 mum P, and 340 to 1025 mum citrate. The high citrate was from plants grown with low P. The major form of Fe in the exudates was Fe citrate. This is probably the form translocated in the plants.
大豆植株（Glycine max (L.) Merrill）在含有 2.5 µm 乙二胺二邻羟苯基乙酸铁（FeEDDHA）和 0 至 128 µm 磷的标准溶液中培养。它们的茎分泌物中含有：32 至 52 µm 的铁、120 至 5000 µm 的磷和 120 至 165 µm 的柠檬酸。高磷条件下分泌液的电泳导致铁尾随，从而无法鉴定任何主要的铁形态。低磷条件下分泌液中则给出了铁柠檬酸的阳极带，为主要的铁化合物。体外添加的磷酸盐会抑制铁柠檬酸峰并导致铁尾随。体外添加的 EDDHA 从铁柠檬酸中提取铁；然后柠檬酸以较慢的形式迁移，铁则以 FeEDDHA 的形式迁移。一种改良的预培养系统，涉及用 0.2 µm 的 FeEDDHA 对 3.2、9.6 或 16 µm 的磷进行为期两天的更新，以及低水平的其他离子，控制了 pH 值的下降并导致柠檬酸和磷水平的显著变化。分泌物中含有：45 至 57 µm 的铁、200 至 925 µm 的磷和 340 至 1025 µm 的柠檬酸。高柠檬酸来自于在低磷条件下生长的植物。分泌物中主要的铁形态是铁柠檬酸。这可能是在植物中转运的形式。
