Table of Contents
Parthenocarpy definition:
The natural or intentionally induced generation of fruit without ovule fertilization, which results in seedless fruit, is known as parthenocarpy. Stenospermocarpy can also yield fruit that appears to be seedless, but the seeds are really aborted when still young. If it affects every flower, parthenocarpy (or stenospermocarpy) develops as a natural mutation; the plant can no longer sexually reproduce but may be able to propagate through apomixis or vegetative mechanisms. Many citrus cultivars, for example, undergo nucellar embryonic reproduction rather than simply sexual reproduction and can produce seedless fruits.
A brief outline:
Stimulative parthenocarpy occurs when pollination or another form of stimulation is required for parthenocarpy in some plants. Vegetative parthenocarpy refers to plants that produce parthenocarpy fruit without pollination or other forms of stimulation. Seedless cucumbers are quite a type of vegetative parthenogenesis, while seedless melon is a type of stenospermocarpy since its seeds are undeveloped (aborted ones). Plants moving from one region of the world to the other may not always be accompanied by their pollination partner, which has prompted the human production of parthenocarpy types. As genetically modified organisms, some parthenocarpy types have been produced. Parthenocarpy of some fruits on a plant, on the other hand, may be useful. Parthenocarpy fruits make up to 20% of wild parsnip fruits. When pollination fails, a plant’s way to generate seedless fruit may be advantageous since it offers nourishment for the plant’s seed dispersers. Seed-spreading animals may starve or relocate if there isn’t a fruit harvest.
Important concepts:
Parthenocarpy classification
Parthenocarpy is classified into three distinct kinds.
- Vegetative parthenocarpy
- Stimulative Parthenocarpy
- Stenospermocarpy
- Vegetative Parthenocarpy:
Vegetative Parthenocarpy is a type of parthenocarpy that grows on plants. Without pollination, this kind of Parthenocarpy occurs, resulting in no seed development within the seeds. Pears and figs, to mention a few, contain it.
- Stimulative Parthenocarpy:
This occurs without pollination as well, but with the addition of an exogenous stimulator. This could be a wasp’s ovipositor put into a flower’s ovary or the injection of plant growth regulators into unisexual flowers found inside the syconium. (A flask-shaped structural line with unisexual flowers is Syconium.)
- Stenospermocarpy:
This is a rare kind of parthenocarpy in which fertilization occurs and the seed develops, but it eventually dies. Within the fruit, there is a seed trace that can be seen, and it can be seen where seed growth stopped. Seedless grapes and watermelons have this form of Parthenocarpy.
Seedless fruit breeders take advantage of immature seeds before they are discarded. Tissue culture techniques are used to cultivate these partially developed seeds from the fruit into plants. Both parents inherit the seedless characteristic, which aids in the development of a large number of seedless offspring.
Parthenocarpy (Natural and Artificial)
- Natural parthenocarpy is a form of parthenocarpy that develops as a result of natural factors such as male sterility, harsh environmental circumstances, a lack of pollinizers and pollinators, and so on.
- Artificial parthenocarpy is a type of parthenocarpy performed with the aid of technology. Artificial parthenocarpy can be achieved using irradiation pollen and the application of plant growth hormones such as auxin and gibberellins, which aid in fruit growth.
Parthenogenesis’ Importance
Because of the following reasons, parthenogenesis is an important process:
- It can be used to determine an individual’s sex, for example, in honey bees, wasps, and other insects, the technique can be used to determine the sex of newly created progeny.
- This method can aid in the eradication of population differences.
- It is a simple and reliable method of replication.
- It can be used to help organisms gain desirable mutant features.
- It can aid in the control of non-adaptive gene combinations.
Commercial Importance
- Inedible fruits with hard seeds, such as bananas, pineapples, oranges, and grapefruits, seedlessness is seen as a desirable characteristic. Fruit crops that are difficult to pollinate or fertilize, such as fig, tomato, and summer squash, benefit from parthenocarpy.
- Parthenocarpy enhances fruit output in dioecious species like persimmon since staminate trees do not need to be planted to give pollen. In nut crops like pistachio, where the seed is the only edible portion, parthenocarpy is undesirable.
- Many plants, including banana, fig, cactus pear (Opuntia), breadfruit, and eggplant, have parthenocarpy cultivars that have been selected and propagated by horticulturists. Because some plants, such as pineapple, are self-infertile, they yield seedless fruits when only one variety is produced.
- If pollinators aren’t present, certain cucumbers develop seedless fruit. Seedless watermelon plants are grown from seeds, as strange as they may appear. To make triploid seeds, a diploid parent is crossed with a tetraploid parent.
Parthenocarpy’s Advantages:
1) This is healthier, and the effects are more straightforward.
2) Improves quality by providing seedless fruits.
3) It lowers the overall cost of growing.
4) This increases agricultural productivity while avoiding the use of organic pesticides.
5) Natural plant growth regulators increase the size of the fruits produced.
6) Because pollinating insects are not required for the production of fruits, parthenocarpy keeps insects and pests at bay without the use of insecticides. Pesticides are not able to harm the plants as a result of this.
Significance of parthenocarpy in NEET exam
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Also read: Important Topic of Biology: Mineral Toxicity
FAQs:
How is parthenocarpy intentionally induced?
Plant growth regulators are used to intentionally induce parthenocarpy. Plant hormones such as gibberellins, auxin, and cytokinin are sprayed on flowers to promote the growth of parthenocarpy fruits.
What are some examples of parthenocarpy fruits?
Parthenocarpy is responsible for the development of fruits such as bananas, cucumbers, grapes, oranges, and pineapple.
What is stimulative parthenocarpy, and how does it work?
When pollination happens but fertilization does not, this type of stimulative parthenocarpy develops. It occurs when a wasp's ovipositor is inserted into the ovary of a flower.
Is it possible to find seedless grapes in nature?
No, seedless grapes aren't found in nature. They are created by asexual reproduction. Some mutant grape varieties, on the other hand, would naturally generate seedless grapes.
