Glutamate-gated receptor that probably acts as non-selective cation channel. Can transport sodium, potassium, and calcium ions. Functions as a carbon and nitrogen regulator and/or sensor that regulates carbon and nitrogen metabolism and distinct physiological process such as germination through the control of acid abscisic (ABA) biosynthesis. May be involved in light-signal transduction and calcium homeostasis via the regulation of calcium influx into cells. Seems required for the regulation of the abscisic acid (ABA) signaling pathway that modulates many aspects of plant physiology such as seed germination and response to drought (e.g. stomata opening). May form heteromers. Expressed predominantly in roots. First detected in the root-shoot junction, and later in lateral roots and at the margin of matures leaves. Increased sensitivity to exogenous abscisic acid (ABA) and higher ABA levels in leaves. Belongs to the glutamate-gated ion channel (TC 1.A.10.1) family.