Catalysis of the reaction: a (9Z,12Z)-octadecadienoyl-containing glycerolipid + 2 H+ + O2 + 2 reduced - = (9Z,12Z,15Z)-octadecatrienoyl-containing glycerolipid + 2 H2O + 2 oxidized -. Also converts a (7Z,10Z)-hexadecadienoyl-containing glycerolipid into a (7Z,10Z,13Z)-hexadecatrienoyl-containing glycerolipid.
linolenate delta15 desaturase activity