at maturity , the enucleate sieve element of primula obconica is lined with a parietal layer of cytoplasm consisting of plasmalemma , one or more cisterna-like layers of endoplasmic reticulum , numerous mitochondria and plastids , and a membrane which apparently separates these cytoplasmic components from a large central cavity .
C0014239
endoplasmic reticulum
C0010834
cytoplasmic