Glutamate-gated receptor that probably acts as non-selective cation channel. May be involved in light-signal transduction and calcium homeostasis via the regulation of calcium influx into cells. Required for the long-term calcium oscillation-regulated stomatal movements. May form heteromers. Expressed predominantly in roots. Firt detected in the vascular tissues of the cotyledons, and later in the vasculature of all organs. In leaves, preferentially expressed in guard cells. Belongs to the glutamate-gated ion channel (TC 1.A.10.1) family. Extended N-terminus. Extended N-terminus.