Introrse

Dehiscence is the splitting at maturity along a built-in line of weakness in a plant structure in order to release its contents, and is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part. Structures that open in this way are said to be dehiscent. Structures that do not open in this way are called indehiscent, and rely on other mechanisms such as decay or predation to release the contents.

A similar process to dehiscence occurs in some flower buds (e.g., Platycodon, Fuchsia), but this is rarely referred to as dehiscence unless dehiscence is involved; anthesis is the usual term for the opening of flowers. Dehiscence may or may not involve the loss of a structure through the process of abscission. The lost structures are said to be .

Manipulation of dehiscence can improve crop yield since a trait that causes seed dispersal is a disadvantage for farmers whose goal is to collect the seed. Many of the agronomically important plants have been bred for reduced shattering.

Explosive dehiscence is a ballistic form of dispersal that flings seeds or spores far from the parent plant. This rapid plant movement can achieve limited dispersal without the assistance of animals. A notable example is the sandbox tree (Hura crepitans), which can fling seeds 100 meters (300 ft) and has been called the "Dynamite tree" due to the loud sound of its explosive dehiscence. Another example is Impatiens, whose explosive dehiscence is triggered by being touched, leading it to be called the "touch-me-not." Explosive dehiscence of sporangia is a characteristic of Sphagnum.

Septicidal and loculicidal dehiscence may not be completely distinct; in some cases both the septa and the walls of the locules split.

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