Parthenocarpy
Encyclopedia
In botany
and horticulture
, parthenocarpy (literally meaning virgin fruit) is the natural or artificially induced production of fruit without fertilization of ovule
s. The fruit is therefore seedless
. Stenospermocarpy
may also produce apparently seedless fruit, but the seeds are actually aborted while still small. Parthenocarpy (or stenospermocarpy) occasionally occurs as a mutation in nature, but if it affects every flower, then the plant can no longer sexually reproduce but might be able to propagate by vegetative
means.
However, parthenocarpy of some fruits on a plant may be of value. Up to 20% of the fruits of wild parsnip
are parthenocarpic. The seedless wild parsnip fruit are preferred by certain herbivores, and thus serve as a "decoy defense" against seed predation
. Utah juniper
has a similar defense against bird feeding. Being able to produce seedless fruit
when pollination
is unsuccessful may be an advantage to a plant because it provides food for the plant's seed dispersers. Without a fruit crop, the seed dispersing animals may starve or migrate.
In some plants, pollination or other stimulation is required for parthenocarpy. This is termed stimulative parthenocarpy. Plants that do not require pollination or other stimulation to produce parthenocarpic fruit have vegetative parthenocarpy. Seedless cucumbers
are an example of vegetative parthenocarpy, seedless watermelon
is an example of stenospermocarpy.
Plants moved from one area of the world to another may not always be accompanied by their pollinating partner and the lack of pollinator
s has spurred human cultivation of parthenocarpic varieties. Some parthenocarpic varieties have been developed as genetically modified organism
s.
is seen as a desirable trait in edible fruit with hard seeds such as pineapple
, banana
, orange
and grapefruit
. Parthenocarpy is also desirable in fruit crops that may be difficult to pollinate or fertilize, such as tomato
and summer squash
. In dioecious
species, such as persimmon
, parthenocarpy increases fruit production because staminate trees do not need to be planted to provide pollen. Parthenocarpy is undesirable in nut crops, such as pistachio
, where the seed is the edible part. Horticulturists have selected and propagated parthenocarpic cultivar
s of many plants, including fig
, cactus pear (Opuntia
), breadfruit
and eggplant. Some plants, such as pineapple, produce seedless fruits when a single cultivar is grown because they are self-infertile. Some cucumber
s produce seedless fruit if pollinator
s are excluded. Strange as it seems, seedless watermelon plants are grown from seeds. The seeds are produced by crossing a diploid parent with a tetraploid parent to produce triploid seeds.
When sprayed on flowers, any of the plant hormone
s gibberellin
, auxin
and cytokinin
can often stimulate the development of parthenocarpic fruit. This is termed artificial parthenocarpy. Plant hormones are seldom used commercially to produce parthenocarpic fruit. Home gardeners sometimes spray their tomatoes with an auxin to assure fruit production.
Some parthenocarpic cultivars have been developed as genetically modified organism
s.
Some parthenocarpic cultivars are of ancient origin. The oldest known cultivated plant is a parthenocarpic fig first grown at least 11,200 years ago.
In some climates, normally seeded pear
cultivars will produce mainly seedless fruit due to lack of pollination.
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
and horticulture
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
, parthenocarpy (literally meaning virgin fruit) is the natural or artificially induced production of fruit without fertilization of ovule
Ovule
Ovule means "small egg". In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: The integument forming its outer layer, the nucellus , and the megaspore-derived female gametophyte in its center...
s. The fruit is therefore seedless
Seedless fruit
A seedless fruit is a fruit developed to possess no mature seeds. As consumption of seedless fruits is generally easier and more convenient, they are considered commercially valuable....
. Stenospermocarpy
Stenospermocarpy
Stenospermocarpy is the biological mechanism that produces seedlessness in some fruits, notably many table grapes. In stenospermocarpic fruits, normal pollination and fertilization are still required to ensure that the fruit 'sets', i.e...
may also produce apparently seedless fruit, but the seeds are actually aborted while still small. Parthenocarpy (or stenospermocarpy) occasionally occurs as a mutation in nature, but if it affects every flower, then the plant can no longer sexually reproduce but might be able to propagate by vegetative
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
means.
However, parthenocarpy of some fruits on a plant may be of value. Up to 20% of the fruits of wild parsnip
Parsnip
The parsnip is a root vegetable related to the carrot. Parsnips resemble carrots, but are paler than most carrots and have a sweeter taste, especially when cooked. The buttery, slightly spicy, sweet flavor of cooked mature parsnips is reminiscent of butterscotch, honey, and subtle cardamom...
are parthenocarpic. The seedless wild parsnip fruit are preferred by certain herbivores, and thus serve as a "decoy defense" against seed predation
Seed predation
Seed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores feed on the seeds of plants as a main or exclusive food source, in many cases leaving the seeds damaged and not viable...
. Utah juniper
Juniperus osteosperma
Juniperus osteosperma is a shrub or small tree reaching 3-6 m tall. It is native to the southwestern United States, in Utah, Nevada, Arizona, western New Mexico, western Colorado, Wyoming, southern Montana, southern Idaho and eastern California...
has a similar defense against bird feeding. Being able to produce seedless fruit
Seedless fruit
A seedless fruit is a fruit developed to possess no mature seeds. As consumption of seedless fruits is generally easier and more convenient, they are considered commercially valuable....
when pollination
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
is unsuccessful may be an advantage to a plant because it provides food for the plant's seed dispersers. Without a fruit crop, the seed dispersing animals may starve or migrate.
Cucumber
The cucumber is a widely cultivated plant in the gourd family Cucurbitaceae, which includes squash, and in the same genus as the muskmelon. The plant is a creeping vine which bears cylindrical edible fruit when ripe. There are three main varieties of cucumber: "slicing", "pickling", and...
are an example of vegetative parthenocarpy, seedless watermelon
Watermelon
Watermelon is a vine-like flowering plant originally from southern Africa. Its fruit, which is also called watermelon, is a special kind referred to by botanists as a pepo, a berry which has a thick rind and fleshy center...
is an example of stenospermocarpy.
Plants moved from one area of the world to another may not always be accompanied by their pollinating partner and the lack of pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...
s has spurred human cultivation of parthenocarpic varieties. Some parthenocarpic varieties have been developed as genetically modified organism
Genetically modified organism
A genetically modified organism or genetically engineered organism is an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one...
s.
Commercial importance
SeedlessnessSeedless fruit
A seedless fruit is a fruit developed to possess no mature seeds. As consumption of seedless fruits is generally easier and more convenient, they are considered commercially valuable....
is seen as a desirable trait in edible fruit with hard seeds such as pineapple
Pineapple
Pineapple is the common name for a tropical plant and its edible fruit, which is actually a multiple fruit consisting of coalesced berries. It was given the name pineapple due to its resemblance to a pine cone. The pineapple is by far the most economically important plant in the Bromeliaceae...
, banana
Banana
Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....
, orange
Orange (fruit)
An orange—specifically, the sweet orange—is the citrus Citrus × sinensis and its fruit. It is the most commonly grown tree fruit in the world....
and grapefruit
Grapefruit
The grapefruit , is a subtropical citrus tree known for its sour fruit, an 18th-century hybrid first bred in Barbados. When found, it was named the "forbidden fruit"; it has also been misidentified with the pomelo or shaddock , one of the parents of this hybrid, the other being sweet orange The...
. Parthenocarpy is also desirable in fruit crops that may be difficult to pollinate or fertilize, such as tomato
Tomato
The word "tomato" may refer to the plant or the edible, typically red, fruit which it bears. Originating in South America, the tomato was spread around the world following the Spanish colonization of the Americas, and its many varieties are now widely grown, often in greenhouses in cooler...
and summer squash
Squash (fruit)
Squashes generally refer to four species of the genus Cucurbita, also called marrows depending on variety or the nationality of the speaker...
. In dioecious
Dioecious
Dioecy is the property of a group of biological organisms that have males and females, but not members that have organs of both sexes at the same time. I.e., those whose individual members can usually produce only one type of gamete; each individual organism is thus distinctly female or male...
species, such as persimmon
Persimmon
A persimmon is the edible fruit of a number of species of trees in the genus Diospyros in the ebony wood family . The word Diospyros means "the fire of Zeus" in ancient Greek. As a tree, it is a perennial plant...
, parthenocarpy increases fruit production because staminate trees do not need to be planted to provide pollen. Parthenocarpy is undesirable in nut crops, such as pistachio
Pistachio
The pistachio, Pistacia vera in the Anacardiaceae family, is a small tree originally from Persia , which now can also be found in regions of Syria, Lebanon, Turkey, Greece, Kyrgyzstan, Turkmenistan, India, Pakistan, Egypt, Sicily and possibly Afghanistan , as well as in the United States,...
, where the seed is the edible part. Horticulturists have selected and propagated parthenocarpic cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s of many plants, including fig
Common fig
The Common fig is a deciduous tree growing to heights of up to 6 m in the genus Ficus from the family Moraceae known as Common fig tree. It is a temperate species native to the Middle East.-Description:...
, cactus pear (Opuntia
Opuntia
Opuntia, also known as nopales or paddle cactus , is a genus in the cactus family, Cactaceae.Currently, only prickly pears are included in this genus of about 200 species distributed throughout most of the Americas. Chollas are now separated into the genus Cylindropuntia, which some still consider...
), breadfruit
Breadfruit
Breadfruit is a species of flowering tree in the mulberry family, Moraceae, growing throughout Southeast Asia and most Pacific Ocean islands...
and eggplant. Some plants, such as pineapple, produce seedless fruits when a single cultivar is grown because they are self-infertile. Some cucumber
Cucumber
The cucumber is a widely cultivated plant in the gourd family Cucurbitaceae, which includes squash, and in the same genus as the muskmelon. The plant is a creeping vine which bears cylindrical edible fruit when ripe. There are three main varieties of cucumber: "slicing", "pickling", and...
s produce seedless fruit if pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...
s are excluded. Strange as it seems, seedless watermelon plants are grown from seeds. The seeds are produced by crossing a diploid parent with a tetraploid parent to produce triploid seeds.
When sprayed on flowers, any of the plant hormone
Plant hormone
Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...
s gibberellin
Gibberellin
Gibberellins are plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction, and leaf and fruit senescence....
, auxin
Auxin
Auxins are a class of plant hormones with some morphogen-like characteristics. Auxins have a cardinal role in coordination of many growth and behavioral processes in the plant's life cycle and are essential for plant body development. Auxins and their role in plant growth were first described by...
and cytokinin
Cytokinin
Cytokinins are a class of plant growth substances that promote cell division, or cytokinesis, in plant roots and shoots. They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth, and leaf senescence...
can often stimulate the development of parthenocarpic fruit. This is termed artificial parthenocarpy. Plant hormones are seldom used commercially to produce parthenocarpic fruit. Home gardeners sometimes spray their tomatoes with an auxin to assure fruit production.
Some parthenocarpic cultivars have been developed as genetically modified organism
Genetically modified organism
A genetically modified organism or genetically engineered organism is an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one...
s.
Some parthenocarpic cultivars are of ancient origin. The oldest known cultivated plant is a parthenocarpic fig first grown at least 11,200 years ago.
In some climates, normally seeded pear
Pear
The pear is any of several tree species of genus Pyrus and also the name of the pomaceous fruit of these trees. Several species of pear are valued by humans for their edible fruit, but the fruit of other species is small, hard, and astringent....
cultivars will produce mainly seedless fruit due to lack of pollination.
Misconceptions
- Most commercial seedless grape cultivars, such as 'Thompson Seedless', are not seedless because of parthenocarpy, but because of stenospermocarpyStenospermocarpyStenospermocarpy is the biological mechanism that produces seedlessness in some fruits, notably many table grapes. In stenospermocarpic fruits, normal pollination and fertilization are still required to ensure that the fruit 'sets', i.e...
. - Parthenocarpy is sometimes claimed to be the equivalent of parthenogenesisParthenogenesisParthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...
in animals. That is incorrect because parthenogenesis is a method of asexual reproduction, and parthenocarpy is not, except in rare cases such as pineapplePineapplePineapple is the common name for a tropical plant and its edible fruit, which is actually a multiple fruit consisting of coalesced berries. It was given the name pineapple due to its resemblance to a pine cone. The pineapple is by far the most economically important plant in the Bromeliaceae...
. The plant equivalent of parthenogenesis is apomixisApomixisIn botany, apomixis was defined by Winkler as replacement of the normal sexual reproduction by asexual reproduction, without fertilization. This definition notably does not mention meiosis...
.