Localizations of OsPIP2;1 in rice root tissues. Rice plants were grown in a hydroponic culture solution and are placed in a growth chamber under a 12 h dark (20 C)/12 h light (25 C) photoperiod (370 μmol s-1 m-2) for 38 d. Tap root samples were fixed at 3 h after the onset of the light period. Root sections at around 4 mm from the root tip were subjected to immunocytochemistry using the anti-OsPIP2;1 antibody. a, Bright field image; b, fluorescent image; c, superimposed image of a and b. Bars represent 50 μm (unpublished, kindly provided by Dr. Junko Sakurai-Ishikawa of NARO Tohoku Agricultural Research Center, Japan).