Abstract
The effect of 21 kJ m-2 d-1 of biologically effective ultraviolet B radiation (UV-BBE) radiation on plant growth, chlorophyll and iron contents, and on iron distribution between root symplastic and extraplasmatic compartments was evaluated in 10 days old maize (Zea mays L.) seedlings grown in nutrient solution. Furthermore, owing to the ability of light to interfere with the redox status of iron complexes, the effect of illumination of the root environment was also studied. The results showed that UV-B radiation had no significant effect on plant growth, whereas illumination of the root environment decreased leaf and root biomass production, regardless of the UV-B radiance. Exposure of plants to UV-B radiation increased both chlorophyll and leaf and root iron contents, in both plants with illuminated and darkened roots. The iron content was much lower in leaves than in roots, where it was mainly located in the extraplasmatic compartment. Illumination of the root environment resulted in higher root iron contents, but this increase was mainly due to the extraplasmatic fraction.