Diaspore (botany)
Encyclopedia
In botany, a diaspore is a plant dispersal unit consisting of a seed
or spore
plus any additional tissues that assist dispersal. In some seed plants, the diaspore is a seed and fruit together, or a seed and elaiosome
. In a few seed plants, the diaspore is most or all of the plant, known as a tumbleweed
.
Diaspores are common in weed
y and ruderal species
. Collectively, diaspores, seeds, and spores that have been modified for migration are disseminules.
by ants (myrmecochory
). This is most notable in Australia
n and South Africa
n sclerophyll
plant communities. Typically, ants carry the diaspore to their nest, where they may eat the elaiosome and discard the seed, and the seed may subsequently germinate
.
A diaspore of seed(s) plus fruit is common in plants dispersed by frugivore
s. Fruit-eating bats typically carry the diaspore to a favorite perch, where they eat the fruit and discard the seed. Fruit-eating birds typically swallow small seeds but, like bats, may carry larger seeded fruits to a perch where they eat the fruit and discard the seed. Diaspores such as achene
s and samara
e are dispersed primarily by wind
; samaras are dispersed also by sailing or tumbling as they fall in still air. Drift fruits and some others are dispersed by water.
Tumbleweeds are dispersed by wind, sometimes over very long distances. These occur in a variety of weed
y and ruderal species
native to steppe
s and desert
s.
Grass
es have various units of dispersal: rarely the caryopsis
alone, often a diaspore. Disarticulation occurs below, between, or above the glumes and at all nodes. Although in some species the diaspore is a foxtail
, in a few (the "tumble grasses") it is like a tumbleweed.
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
or spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
plus any additional tissues that assist dispersal. In some seed plants, the diaspore is a seed and fruit together, or a seed and elaiosome
Elaiosome
Elaiosomes are fleshy structures that are attached to the seeds of many plant species. The elaiosome is rich in lipids and proteins, and may be variously shaped. Many plants have elaiosomes to attract ants, which take the seed to their nest and feed the elaiosome to their larvae...
. In a few seed plants, the diaspore is most or all of the plant, known as a tumbleweed
Tumbleweed
A tumbleweed is the above-ground part of a plant that, once mature and dry, disengages from the root and tumbles away in the wind. Usually, the tumbleweed is the entire plant apart from the roots, but in a few species it is a flower cluster. The tumbleweed habit is most common in steppe and desert...
.
Diaspores are common in weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
y and ruderal species
Ruderal species
A ruderal species is a plant species that is first to colonize disturbed lands. The disturbance may be natural , or due to human influence – constructional , or agricultural .Ruderal species typically dominate the disturbed area...
. Collectively, diaspores, seeds, and spores that have been modified for migration are disseminules.
Role in dispersal
A diaspore of seed plus elaiosome is a common adaptation to seed dispersalSeed 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. Seeds can be dispersed away from the parent plant...
by ants (myrmecochory
Myrmecochory
Myrmecochory is seed dispersal by ants, an ecologically significant ant-plant interaction with worldwide distribution. Myrmecochorous plants produce seeds with elaiosomes, a term encompassing various external appendages or "food bodies" rich in lipids, amino acid, or other nutrients that are...
). This is most notable in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n and South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
n sclerophyll
Sclerophyll
Sclerophyll is the term for a type of vegetation that has hard leaves and short internodes . The word comes from the Greek sclero and phyllon ....
plant communities. Typically, ants carry the diaspore to their nest, where they may eat the elaiosome and discard the seed, and the seed may subsequently germinate
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
.
A diaspore of seed(s) plus fruit is common in plants dispersed by frugivore
Frugivore
A frugivore is a fruit eater. It can be any type of herbivore or omnivore where fruit is a preferred food type. Because approximately 20% of all mammalian herbivores also eat fruit, frugivory is considered to be common among mammals. Since frugivores eat a lot of fruit they are highly dependent...
s. Fruit-eating bats typically carry the diaspore to a favorite perch, where they eat the fruit and discard the seed. Fruit-eating birds typically swallow small seeds but, like bats, may carry larger seeded fruits to a perch where they eat the fruit and discard the seed. Diaspores such as achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
s and samara
Samara (fruit)
A samara is a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit and indehiscent . It is a winged achene...
e are dispersed primarily by wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
; samaras are dispersed also by sailing or tumbling as they fall in still air. Drift fruits and some others are dispersed by water.
Tumbleweeds are dispersed by wind, sometimes over very long distances. These occur in a variety of weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
y and ruderal species
Ruderal species
A ruderal species is a plant species that is first to colonize disturbed lands. The disturbance may be natural , or due to human influence – constructional , or agricultural .Ruderal species typically dominate the disturbed area...
native to steppe
Steppe
In physical geography, steppe is an ecoregion, in the montane grasslands and shrublands and temperate grasslands, savannas, and shrublands biomes, characterized by grassland plains without trees apart from those near rivers and lakes...
s and desert
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...
s.
Grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
es have various units of dispersal: rarely the caryopsis
Caryopsis
In botany, a caryopsis is a type of simple dry fruit — one that is monocarpelate and indehiscent and resembles an achene, except that in a caryopsis the pericarp is fused with the thin seed coat....
alone, often a diaspore. Disarticulation occurs below, between, or above the glumes and at all nodes. Although in some species the diaspore is a foxtail
Foxtail (diaspore)
A foxtail is a spikelet or spikelet cluster of a grass, that serves to disperse its seeds as a unit. Thus, the foxtail is a type of diaspore or plant dispersal unit. Some grasses that produce a foxtail are themselves called "foxtail", also "spear grass"...
, in a few (the "tumble grasses") it is like a tumbleweed.
See also
- Foxtail (diaspore)Foxtail (diaspore)A foxtail is a spikelet or spikelet cluster of a grass, that serves to disperse its seeds as a unit. Thus, the foxtail is a type of diaspore or plant dispersal unit. Some grasses that produce a foxtail are themselves called "foxtail", also "spear grass"...
- LichenLichenLichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
- PropagulePropaguleIn horticulture, a propagule is any plant material used for the purpose of plant propagation. In asexual reproduction, a propagule may be a woody, semi-hardwood, or softwood cutting, leaf section, or any number of other plant parts. In sexual reproduction, a propagule is a seed or spore...
- SeedbankSeedbankA seedbank stores seeds as a source for planting in case seed reserves elsewhere are destroyed. It is a type of gene bank. The seeds stored may be food crops, or those of rare species to protect biodiversity. The reasons for storing seeds may be varied...
- Soil seed bankSoil Seed BankThe soil seed bank refers to the natural storage of seeds, often dormant, within the soil of most ecosystems. The study of soil seed banks started in 1859 when Charles Darwin observed the emergence of seedlings using soil samples from the bottom of a lake. The first scientific paper on the subject...
- SporogenesisSporogenesisSporogenesis is the production of spores in biology. The term is also used to refer to the process of reproduction via spores. Reproductive spores are formed in many eukaryotic organisms, such as plants, algae and fungi, during their normal reproductive life cycle...
- WolffiaWolffiaWolffia is a genus of 9 to 11 species which include the smallest flowering plants on Earth. Commonly called watermeal or duckweed, these aquatic plants resemble specks of cornmeal floating on the water. Wolffia species are free-floating thalli, green or yellow-green, and without roots. The flower...