WordNet records no synonym and no antonym for dehiscence. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
(biology) release of material by splitting open of an organ or tissue; the natural bursting open at maturity of a fruit or other reproductive body to release seeds or spores or the bursting open of a surgically closed wound
Synonyms, antonyms and the broader and narrower relations for dehiscence come from Princeton University’s WordNet. Full sources and licences.