Parthenocarpy

Parthenocarpy is a process in plants that results in fruit development without the fertilization of the ovule. This process has found its importance in agriculture and horticulture as it yields seedless fruits with enhanced quality. Moreover, it does not depend on external environmental factors and promises consistent fruit yield. The fruits that result from parthenocarpy are termed parthenocarpic fruit or virgin fruits. Parthenocarpy has been an important topic of research since ancient times. Primarily it was a natural phenomenon recognized for the first time by Greeks. With the evolution of agricultural science artificial parthenocarpy was introduced and served as a giant leap in food production technology.

What is Parthenocarpy?

Some plants produce fruits that either do not have seeds or have non-viable seeds. Such fruits are called virgin fruits. Ideally these fruits were produced without the fertilization of the ovule and the process that resulted in development of such virin fruits is called parthenocarpy. The term parthenogarpy was derived from two greek words ‘parthenos’ that meant virgin and ‘karpos’ that meant fruit. Parthenocarpy is a well studied phenomena of the plant kingdom. It can be caused by several factors that could be either genetic or external. Earlier it was seen to be occuring naturally in some varieties of fruits like bananas and grapes. However, in a very short period of time humans intervened to produce virgin fruits artificially.

Examples of Parthenocarpy

Some common examples of Pathenocarpy can be seen in different types of bananas, grapes, seedless watermelons, egg plants, etc. Some varieties of citrus fruits also undergo parthenocarpy and yield seedless fruits. These fruits have high commercial values due to the convinience of consumption and less dependency on external factors like climate and pollinators.

Causes of Pathenocarpy

Occurence of parthenocarpy can be credited to several factors. These factors can be genetic, non-genetic, or a combined effect of both. Some of these causes are discussed below:

1. Genetic factors: Some plant varieties have natural tendency to produce parthenocarpic fruits due to their genetic composition. For example plants like banana, pineapple, eggplant, etc.
2. Hormones: Certain plant hormones like auxins, gibberellins, etc. play an important role in development and maturation of fruit. Altering the balance of these hormones can induce fruiting without fertilization.
3. Failed pollination: Sometimes pollination fails but the chemical mechanism that get triggered due to the act of pollination leads to fruit development even if the fertilization fails.
4. Stress: Sometimes environmental stress can result in induction of parthenocarpy. For example, low temperature condition can result in production of parthenocarpic fruits in members of Cucurbitaceae.
5. Chemical inuctions and mutation: Sometimes plants are treated with certain chemicals that trigger fruiting without fertilization. Apart from this, spontaneous or induced mutations can also result in parthenocarpic fruit production.

Types of Parthenocarpy

Parthenocarpy can be primarily classified into two types: Natural or Induced. However, based on the part of plant that gives rise to the fruit and the mechanism through which the fruit develops, parthenocarpy can be classified as vegetative parthenocarpy or stimulative parthenocarpy.

Vegetative Parthenocarpy

When parthenocarpic develop without pollination and from an unfertilized ovule, the parthenocarpy is said to be vegetative parthenocarpy. Vegetative parthenocarpy can result in development of fruit from unfertilized ovules or vegetative parts of plants.Vegetative parthenocarpy is more or less a natural phenomana. However, over the years horticulturists have developed methods to induce this artificially.

Stimulative Pathenocarpy

Stimulative parthenocarpy occurs when parthenocarpy is induced by external factors like chemicals. Such parthenocarpy can be classified as hormone induced parthenocarpy or mutation induced parthenocarpy. This process has developed mainly due the increased demands of seedless fruits. Stimulative parthenocarpy is ideally termed as artificial parthenocarpy. However, sometimes natural alteration of environmental conditions can result in natural stimulation of parthenocarpy.

Parthenocarpic Fruits

Fruits that result from parthenocarpy are called parthenocarpic fruits. They are called virgin fruits as they do not contain viable seeds. Ideally, parthenocarpic fruits are seedless as their ovules do not get fertilized. Sometimes fruits may have rudimentary seed that failed to mature. Examples of parthenocarpic fruits include seedless watermelons, bananas, grapes, etc.

Advantages of Parthenocarpy

Since parthenocarpy prouces fruits without fertilization, it has several advantages. Some of these advantages are listed below:

1. Reduced dependencies on pollinators: Parthenocarpy results is production of good quality of fruit even when pollination does not take place. It ensures fruit yield even when the pollinators are absent. This in turn results in more predictable and consistent yield even in environment where pollinating agents may be scarce.
2. High marketability or economic value: Patthenocarpic fruits are easily marketable because of the absence of seeds that make them easier to eat. Moreover, parthenocarpic plants yield fruits of consistent quality generation after generation.
3. Extended growing season: Parthenocarpic plants can fruit even during unfavourable conditions of pollination. This results in extended season for growth. Thus ensuring greater and longer yield.
4. Reduced susceptibility to diseases: Sometimes diseases can get transmitted during pollination or due to combination of genes during seed formation. Since parthenocarpic fruits can develop in absence of pollination or fertilization, they are less susceptible to diseases.
5. Ease of Cultivation: Plants that exhibit parthenocarpy are of extreme advantages to their cultivators since they do not have to depend on any external factors like pollinators, weather condition, etc. to predict their yield. Chances of crop loss is highly reduced for them. They can grow their crops even under unfavourable conditions and get enhanced crop quality.

Disadvantages of Parthenocarpy

Along with advantages, parthenocarpy has several disadvantages also. Some of these disadvantages are discussed below:

1. Reduced genetic diversity: Plants that exhibit parthenocarpy usually propagate through asexual modes. This leads to the lack of genetic diversity. As a result, some detrimental genes get fixed and chances of developing new genes are rare. This results in reduced vigour and plants also become susceptible to diseases.
2. Need for human intervention increased: Some parthenocarpic plants require specific conditions or treatments to induce fruit development. This can make them more dependent on human intervention. Yield in such case is completely based on the human expertise.
3. Cost: Some plant varieties need application of different chemicals and undergo various treatments that are both cost and labor intensive. In such cases, cultivation of parthenocarpic varieties become costly, especially for small farms.
4. Ecological impacts: Parthenocarpy is no doubt a fabulous process that has eliminated the need for pollinators and thereby increased the fruiting season of parthenocarpic varieties. However, it has several potentially negative impact on the ecosystem. Like, reduced fertility and less genetic diversity can result in more susceptibilty and less adaptability to diseases and environmental conditions respectively. This can result in extinction of a given species over time. Apart from this, the lack of seeds in parthenocarpic fruits may impact the ecology in terms of reduced food sources for seed-dispersing animals.

Lastly, parthenocarpy is a fascinating process that results in production of seedless fruits with enhanced quality. It is a significant process in agriculture and horticulture as it raises the econimic value of the yield. It occurs naturally in fruits like bananas and pineapples but can be induced artificially as well. It can broadly be classified as vegetative parthenocarpy and stimulative parthenocarpy based on their mechanism of occurence. It has been an important topic of research in field of agricultural technology and promises sustainable and efficient food production.

FAQ’s on Parthenocarpy

1. How Parthenocarpy is Different from Apomixis?

Parthenocarpy is the development of fruit without fertilization in plants and results in production seedless fruits. Apomixis, on the other hand, is a form of asexual reproduction where seeds are produced without fertilization. While both processes involve reproduction without the involvement of male gametes, they occur at different stages of plant development and have distinct mechanisms.

2. Is Stenospermocarpy a Type of Parthenocarpy?

No, Stenospercarpy is not a type of parthenocarpy.Stenospermocarpy refers to the phenomenon where seeds within a fruit are significantly reduced in size, often to the point of being non-functional or sterile.This condition is distinct from parthenocarpy, where fruits develop without fertilization, as stenospermocarpy primarily focuses on the reduced development or absence of viable seeds within the fruit.

3. Name some Plants that Exhibit Natural Parthenocarpy?

Some plants that exhibit natural parthenocarpy are bananas, pineapples, cucumbers, grapes, and eggplants.

4. How does Parthenocarpy differs from Parthenogenesis?

Parthenocarpy and parthenogenesis are distinct biological processes. Parthenocarpy occurs in plants, and leads to fruit development without fertilization. On the other hand, parthenogenesis occurs in animals, and involves the development of embryos from unfertilized eggs. Parthenocarpy results in production of seedless fruits whereas parthenogenesis results in offsprings exactly identical to their mothers or haploid offsprings that are sterile.

5. What are the Benefits of Parthenocarpy?

Parthenocarpy has several benefits like seedless fruit production, reduced dependency on pollinators, assurance of consistent and predictable yields, extended growing season, making cultivation more resilient to environmental factors. Moreover, parthenocarpic plants are less susceptible to diseases transmitted during pollination, and their genetic aspects can be studied for potential use in genetic engineering to enhance crop productivity.