Glutamate-gated receptor that probably acts as non-selective cation channel (Probable). May be involved in light-signal transduction and calcium homeostasis via the regulation of calcium influx into cells (Probable). Could play a role in calcium unloading from the xylem vessels (PubMed:11158446). Acts as negative regulator of lateral root initiation and development (PubMed:23590882). May restrict primordia numbers and position along the root axis by a signaling process originating in the phloem (PubMed:23590882). Forms a heteromeric channel with GLR3.4. Localizes to the plasma membrane. Expressed in leaves and siliques, and at lower level in flowers and roots (PubMed:12082126). Detected in the vascular tissues of both shoots and roots (PubMed:11158446, Ref.7). Expressed in root phloem (PubMed:23590882). Overproduction and aberrant placement of lateral root primordia. Overexpression of the gene leads to calcium deficiency and hypersensitivity to potassium and sodium. Belongs to the glutamate-gated ion channel (TC 1.A.10.1) family.