Indehiscence

Indehiscence is a botanical term describing a fruit or sporangium that does not open at maturity to release its seeds. It is the opposite of dehiscence, in which a fruit splits open along defined sutures to shed seeds. Indehiscent fruits retain seeds inside a closed pericarp or ovary, and seed dispersal typically occurs through other means.

Indehiscent fruit types include nuts (acorns, chestnuts), grains or caryopses (rice, wheat), and true seeds enclosed in a non-splitting fruit such as achenes (sunflowers) and various drupes and pomes (peaches, plums, apples, pears). In these fruits, the whole fruit or seeds are dispersed intact, often by animal ingestion, gravity, water, or decay of the fruit tissue, rather than by mechanical release.

Indehiscence can be an adaptive feature linked to specific dispersal strategies. For example, nuts and drupes commonly rely on animals for transport and caching, while grains and achenes can be dispersed passively or after the fruit degrades. Evolutionary shifts between indehiscence and dehiscence occur in many plant lineages and are associated with shifts in ecology and life history.

In horticulture and agriculture, indehiscence affects seed collection and propagation. Crops such as cereals produce indehiscent grains that must be harvested with seeds still attached to the fruit, and nut crops require processing to access the seeds.