Dehiscence (botany) - Fruit Dehiscence

Fruit Dehiscence

There are many different types of fruit dehiscence, that involve different types of structures. Some fruits are indehiscent, and not open to disperse the seeds. Xerochasy is dehiscence that occurs upon drying, and hygrochasy is dehiscence that occurs upon wetting. Dehiscent fruits that are derived from one carpel are follicles or legumes, and those derived from multiple carpels are capsules or siliques.

One example of a dehiscent fruit is the silique. This fruit develops from a gynoecium composed of two fused carpels, which, upon fertilization, grow to become a silique that contains the developing seeds. After seed maturation, dehiscence takes place, and valves detach from the central septum freeing the seeds. This is also known as shattering and can be important as a seed dispersal mechanism. This process is similar to anther dehiscence and the region that breaks (dehiscence zone) runs the entire length of the fruit between the valves (the outer walls of the ovary) and the replum (the persisting septa of the ovary). At maturity, the dehiscence zone is effectively a non-lignified layer between two regions of lignified cells in the valve and the replum. Shattering occurs due to the combination of cell wall loosening in the dehiscence zone and the tensions established by the differential mechanical properties of the drying cells.

• Poppy fruit showing poricidal dehiscence; the seeds exit through pores beneath the "crown"

• Peanuts: an indehiscent (subterranean) fruit

• Thlaspi arvense, with fruit that are dehiscent siliques

• Ledum capsules have septicidal dehiscence; the fruit splits through the septa between the carpels

• Iridaceae capsules have loculicidal dehiscence; the fruit splits through the ovary wall of each carpel, allowing the seeds to exit directly from the locule

• Anagallis fruits open with circumscissile dehiscence. A small cap separates from the remainder of the fruit along a circular horizontal zone.