At 14 dpi, in nitrogen fixation zone, many mature bacteroids in
nZnO-treated cellswere elongated or in Y-shape (Fig. 10b–c) as the controls
(Fig. 10a). However, cells treatedwith 750 mg/L of nZnO contained
less cytoplasmic organelles (Fig. 10c). Nodules exposed to nZnO were
still unable to form normal infection threads. The infection threads in
the controlled nodules had a normal pattern with thin cell wall
(Fig. 10d); whereas the infection threads in nZnO-treated cells were
either irregular in shape with excess wall matrix (Fig. 10e) or with abnormally
degraded wall (Fig. 10f). Fan et al. (2014) also reported