Total TiO<sub>2</sub> suspended or sedimented in the hydroponic system.

<p>Red clover was exposed (n = 3) over 162 h to the two nanoparticles P25 and E171. TiO<sub>2</sub> amounts of the pooled stock suspension is shown at t = 0 in black. TiO<sub>2</sub> amounts of the top (white, 17 ml, in contact with roots) and bottom part (grey, 3 ml, including precipitate) are shown. Differences of the total TiO<sub>2</sub> NP amount (bottom and top part together) to the total Ti amount at t = 0 are indicated with asterisks (p<0.05). Error bars indicate standard deviations (n = 3).</p>