ABSTRACT

The relation between chemical attributes of complexed Fe sources and the efficiency of foliar fertilization is still unclear. This study aimed to investigate the influence of Fe-complex stability on iron accumulation and redistribution in maize by foliar application. The iron complexing agents used were biodegradable citric acid (CA), malic acid (MA), tartaric acid (TA), and oxalic acid (OA). The prepared FeSO₄ based complexes in the foliar spray solutions had ‘Fe: organic acid’ stoichiometric ratios of 1:1 and 1:2. Additionally, Fe-EDTA and FeSO₄ were also tested. The iron complexed fraction and the main complexed chemical species in the foliar spray solutions were determined using the Minteq software. Molecular modeling helped obtain probable complex structures and stabilities. The parameters, such as dry maize matter, shoot N accumulation, SPAD index, Fe-shoot, and Fe-root accumulation were determined. The complexes with TA and CA prepared at the stoichiometric ratio 1:2 showed the most favorable results in plant growth, iron nutrition. The stability and solubility of complexes affected iron accumulation and plant growth. The results indicate that iron redistribution to the roots increased in tandem with complex stability. Additionally, shoot iron accumulation was more significant for complexes with high solubility and low stability.

摘要

复合铁源的化学属性与叶面施肥效率之间的关系尚不清楚。本研究旨在探讨铁络合物稳定性对叶面喷施玉米铁积累和再分配的影响。使用的铁络合剂是可生物降解的柠檬酸 (CA)、苹果酸 (MA)、酒石酸 (TA) 和草酸 (OA)。在叶面喷雾溶液中制备的基于 FeSO ₄的配合物具有 1:1 和 1:2 的“Fe:有机酸”化学计量比。此外，Fe-EDTA 和 FeSO ₄也进行了测试。使用 Minteq 软件测定叶面喷雾溶液中的铁络合部分和主要络合化学物质。分子建模有助于获得可能的复杂结构和稳定性。测定了玉米干物质、芽氮积累、SPAD 指数、铁芽和铁根积累等参数。以化学计量比 1:2 制备的 TA 和 CA 复合物在植物生长、铁营养方面表现出最有利的结果。络合物的稳定性和溶解度影响铁的积累和植物生长。结果表明，铁在根部的再分配随着复杂稳定性的增加而增加。此外，对于高溶解度和低稳定性的配合物，芽铁积累更为显着。