a (3R)-hydroxyacyl-[ACP] + NADP(+) = a 3-oxoacyl-[ACP] + H(+) + NADPH Lipid metabolism; fatty acid biosynthesis. Homotetramer. And non-photosynthetic plastids. Embryo and leaf tissues. Exhibits a marked preference for acyl-carrier protein derivatives over CoA derivatives as substrates. Belongs to the short-chain dehydrogenases/reductases (SDR) family.