The present experimental investigation is focused on the study of assimilatory pigments and nucleic acid levels in young plants intended for agricultural use (Zea mays) in presence of water based magnetic fluid added in culture medium. The magnetic fluid was constituted by coating the nanosized magnetic nanoparticles (with 10.55 nm average value of the physical diameter) with β-cyclodextrin (C 42 H 70 O 35 ) and further dispersion in water. After germination, various volume fractions (between 10 mL/L and 500 mL/L) of the magnetic fluid was added daily in the culture medium of Zea mays plants still at their early ontogenetic stages. Toxicity symptoms leaded to brown spots covering the leaf surface for the highest magnetic fluid volume fractions used, a putative oxidative stress generated by iron excess treatment. Relatively small volume fraction of magnetic fluid solutions induced the increase of chlorophyll a level (up to 38%), the main photosynthesis pigment, as well that the nucleic acid level (up to 57%) in Zea mays plantlets. All volume fractions of magnetic fluid solutions analyzed may have severe disruptive effects such as the ratio chlorophyll a/chlorophyll b (about 50% decreasing).