Reductase involved in the lignan justicidin B biosynthesis. Catalyzes the enantioselective conversion of (+)-pinoresinol into (+)-lariciresinol and of (-)-lariciresinol into (+)-secoisolariciresinol. Low activity with the other enantiomers. Abstracts the 4R-hydride from the NADPH cofactor during catalysis. (+)-lariciresinol + NADP(+) = (+)-pinoresinol + H(+) + NADPH (+)-secoisolariciresinol + NADP(+) = (-)-lariciresinol + H(+) + NADPH Dimer. Unlike most other PLRs, this enzyme has an opposite enantiospecificity within the two reaction steps. Belongs to the NmrA-type oxidoreductase family. Isoflavone reductase subfamily.