Hydrolyzes glycerol-phospholipids at the terminal phosphodiesteric bond to generate phosphatidic acids (PA). May be involved in PA accumulation in the dehydration stress response and in the transduction of hormonal and environmental signals to the microtubules cytoskeleton (PubMed:11549769, PubMed:11489173, PubMed:12881496). Prefers phosphatidylethanolamine to phosphatidylcholine as substrate (PubMed:12397060). Involved in H(2)O(2) and abscisic acid (ABA)-induced stomatal closure (PubMed:22589465, PubMed:22392280). Involved in nitric oxide (NO) signaling during stomatal closure (PubMed:22932846). Plays a positive role in ABA-promoted senescence (PubMed:23762411). Involved in basal defense and nonhost resistance (PubMed:23979971). a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1,2-diacyl-sn-glycero-3-phosphate + choline + H(+) Ca(2+). Requires millimolar level (PIP2-dependent). Activated by free oleic acid in a dose-dependent manner and less effectively by other unsaturated fatty acids such as linoleic and linolenic acids (PubMed:11706190). Not activated by the saturated fatty acids stearic and palmitic acids (PubMed:11706190). PIP2 and Ca(2+) stimulate activity by promoting lipid substrate binding to the active site (PubMed:12397060). Activated by H(2)O(2) and by binding to GAPC (PubMed:14508007, PubMed:22589465). Optimum pH is between 6.0 and 7.0. Interacts with GAPC1 and GAPC2. Increased interaction in the presence of H(2)O(2). Colocalization with cortical microtubules also occurs. Expressed in roots, leaves, stems, siliques and flowers (PubMed:11706190, PubMed:11489173). Strongly expressed in the vascular tissues of cotyledons and leaves under dehydration stress conditions (PubMed:11489173). Expression is higher in old leaves than in young leaves (PubMed:11706190). Expressed in leaves and guard cells (PubMed:22932846). The isoform 2 may not be present in siliques. By salt stress or dehydration, in vascular tissues of roots, cotyledons and leaves (PubMed:11489173, PubMed:19017627). Not induced cold stress (PubMed:11489173). Up-regulated by abscisic acid in rosette leaves (PubMed:22932846, PubMed:22392280). C2 domain is a calcium-binding fold, and the binding promotes the protein association with membranes. In PLD delta, all the calcium-coordinating acidic amino acids are conserved. No visible phenotype when grown under standard conditions (PubMed:22932846). Loss of oleate-activated PLD activity and increased sensitivity to stress damage and to H(2)O(2)-induced cell death (PubMed:14508007). Hypersensitivity to hyperosmotic stress (PubMed:19017627). Impaired stomatal closure in response to nitric oxide donor (PubMed:22932846). Attenuated lipid degradation retarding abscisic acid (ABA)-promoted leaf senescence (PubMed:23762411). Decreased penetration resistance against non-host fungi (PubMed:23979971). No effect on ABA-induced stomatal closure (PubMed:22392280). Pldalpha1 and plddelta double mutants have a suppressed ABA-induced stomatal closure (PubMed:22392280). Belongs to the phospholipase D family. C2-PLD subfamily.