Effect of different Fe(III) compounds on photosynthetic electron transport in spinach chloroplasts and on iron accumulation in maize plants

摘要

Synthesis and spectral characteristics of [Fe(nia)(3)Cl-3] and [Fe(nia)(3)(H2O)(2)](ClO4)(3) are described. The effect of these compounds as well as of FeCl3 center dot 6H(2)O on photosynthetic electron transport in spinach chloroplasts was investigated using EPR spectroscopy. It was found that due to the interaction of these compounds with tyrosine radicals situated at the 161(st) position in D-1 (Tyr(Z)) and D-2 (Tyr(D)) proteins located at the donor side of photosystem (PS) II, electron transport between the photosynthetic centres PS II and PS I was interrupted. In addition, the treatment with [Fe(nia)(3)(H2O)(2)](ClO4)(3) resulted in a release of Mn(II) from the oxygen evolving complex situated on the donor side of PS II. Moreover, the effect of the Fe(III) compounds studied on some production characteristics of hydroponically cultivated maize plants and on Fe accumulation in plant organs was investigated. In general, the production characteristic most inhibited by the presence of Fe(III) compounds was the leaf dry mass and [Fe(nia)(3)(H2O)(2)](ClO4)(3) was found to be the most effective compound. The highest Fe amount was accumulated in the roots, and the leaves treated with Fe(III) compounds contained more Fe than the stems. The treatment with FeCl3 center dot 6H(2)O caused the most effective translocation of Fe into the shoots. Comparing the effect of nicotinamide complexes, [Fe(nia)(3)(H2O)(2)](ClO4)(3) was found to facilitate the translocation of Fe into the shoots more effectively than [Fe(nia)(3)Cl-3]. This could be connected with the different structure of these complexes. [Fe(nia)(3)(H2O)(2)](ClO4)(3) has ionic structure and, in addition, coordinated H2O molecules can be easily substituted by other ligands. (C) 2008 Institute of Chemistry, Slovak Academy of Sciences.