Dehiscence (botany)

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Dehiscence (botany)

Dehiscence is the spontaneous opening at maturity of a plant structure, such as a fruit

Fruit

The term fruit has different meanings dependent on context, and the term is not synonymous in food preparation and biology. In botany, which is the scientific study of plants, fruits are the ripened Ovary of flowering plants....
, anther, or sporangium

Sporangium

A sporangium is a plant or fungus structure producing and containing spores. Sporangia occur in Flowering plant, gymnosperms, ferns, fern allies, bryophytes, Algaee, and Fungus....
, to release its contents.

is the final function of the anther that causes the release of pollen grains. The anther wall breaks at a specific site that runs the length of the anther. This site is observed as an indentation between the locules of each theca

Theca

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Dehiscence is the spontaneous opening at maturity of a plant structure, such as a fruit

Fruit

Sporangium

Anther dehiscence

This is the final function of the anther that causes the release of pollen grains. The anther wall breaks at a specific site that runs the length of the anther. This site is observed as an indentation between the locules of each theca

Theca

A theca refers to any case, covering, or sheath.In botany, the theca of an angiosperm is half of the anther. An anther and its filament form together a typical stamen, part of the male flower organ....
.

The stomium, and septum are two specialised cell types present at this site. The degeneration of the stomium and septum cells is part of a developmentally timed cell-death program. Initially the septum degenerates thereby establishing the stomium as the future site of anther wall breakage and pollen release. Expansion of the endothecial

Endothecium

Endothecium is a type of tissue found in the walls of anthers and in moss capsules. This tissue is usually one to several layers thick, and is composed of cells that have walls of uneven thickness....
layer and lignification of the endothecial cell walls are required for dehiscence.

The process of anther dehiscence is coordinated precisely with pollen differentiation, floral development, and flower opening.

Fruit dehiscence

Typically a fruit develops from a gynoecium composed of fused carpels, which, upon fertilization, grow to become a silique

Silique

A silique is a fruit of 2 fused carpels that separate when ripe, leaving a peristant partition, with the length being more than twice the width....
that contains the developing seed

Seed

A seed is a small Plant embryogenesis plant enclosed in a covering called the seed coat, usually with some Food storage. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant....
s. 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

Seed dispersal

Seed dispersal is the movement or transport of seeds away from the parent plant. Plants have limited mobility and consequently rely upon a variety of dispersal vectors to transport their propagules, including both abiotic and biotic vectors....
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 and the replum (external septum).

At maturity, the dehiscence zone is effectively a non-lignified layer between a region 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 in the silique.

Xerochasy is dehiscence that occurs upon drying; conversely, hygrochasy is dehiscence that occurs upon wetting.

Association with crop breeding

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.