plastid membrane periplastidial membrane https://github.com/geneontology/go-ontology/issues/31421 PPM 2026-01-29T01:11:34Z GO:7770041 The lipid bilayer that forms the second outermost membrane of complex plastids in organisms that acquired their plastids through secondary endosymbiosis. The periplastidial membrane is evolutionarily derived from the plasma membrane of the engulfed algal endosymbiont and together with the outer envelope membrane of the plastid defines the periplastidial compartment. cellular_component dragon-ai-agent