Parthenocarpy

What Is Parthenocarpy?

Parthenocarpy is the growth of fruit without the fertilisation of ovules. Hence, parthenocarpous fruits grow without seeds. This is very important in agriculture and horticulture since it means desirable fruits can be grown on plants without the need for pollination, and extra energy intake for seed development is avoided. Investigations of parthenocarpy have given insight into reproduction in plants and also into ways through which crop yields can be enhanced.

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Characteristics Of Parthenocarpy

Parthenocarpy is a unique method of fruit formation that is controlled by plant hormones and does not involve sexual reproduction. The main characteristics of parthenocarpy are given below:

• Fruit Development: Parthenocarpy provides for fruit formation without the process of pollination or fertilisation.

• Seedless Fruits: Since parthenocarpic fruits develop in the absence of the stimulus of fertilisation, they are seedless.

• Gene Uniformity: Parthenocarpic plants give rise to offspring that are genetically identical since it does not involve sexual reproduction.

• Hormonal Control: The growth of parthenocarpic fruits is normally controlled by plant hormones like auxins and gibberellins.

• Agricultural Applications: Parthenocarpy has huge potential in agriculture for growing seedless fruits with certain very admirable characteristics.

Types Of Parthenocarpy

Parthenocarpy can be broadly classified into two types based on stimuli that induce the development of fruit:

1. Stenospermocarpy

• In stenospermocarpy, there is pollination and partial fertilisation, but it undergoes degeneration of the embryo and endosperm at an early stage, resulting in seedless fruits.

• Examples include seedless grapes and bananas.

2. Autonomic Parthenocarpy

• Autonomous parthenocarpy refers to the development of fruits without a stimulus from an outside source, for example, pollination or fertilisation.

• This type of parthenocarpy may be artificially initiated by the application of plant growth regulators or through genetic manipulation.

• Examples include parthenocarpic tomatoes and cucumbers.

Parthenocarpic Fruits

Parthenocarpic fruits are seedless fruits that develop in the absence of fertilisation in plants. These fruits become very desirable in most agricultural and horticultural contexts for reasons of convenience, taste, and texture.

Examples Of Parthenocarpic Fruits

• Bananas: Several banana cultivars are parthenocarpic and give way to seedless fruits.

• Grapes: Thompson Seedless and Flame Seedless are two examples of popular grapes without seeds that are parthenocarpic varieties.

• Citrus Fruits: Some citrus fruits, such as mandarins and clementines, can grow to be parthenocarpic.

• Pineapples are examples of parthenocarpic fruits and grow from multiple flowers merged into one.

Advantages Of Parthenocarpy

Parthenocarpy offers several benefits to both farmers and consumers. Since fruits develop without fertilization, they are usually seedless, uniform, and of better quality. Some of the advantages are given below:

• Improved Fruit Quality: As a rule, parthenocarpic fruits are tastier, have better texture, and look better than seeded fruits.

• Reduced Seed Production: The seedlessness in parthenocarpic fruits increases their consumer appeal and reduces wastage during their consumption.

• Higher Yield: Parthenocarpy can result in higher fruit yields because more of the energies of the plant are used in fruit development rather than seed formation.

• Genetic Uniformity: The offspring of parthenocarpic plants all have the same genetic constitution, making them good for breeding and cultivation.

Problems and Limitations Of Parthenocarpy

Parthenocarpy is useful for producing seedless fruits, but it also has some drawbacks. This section explains the main problems and limitations related to its use in agriculture.

• Lowered Genetic Diversity: Without sexual reproduction in parthenocarpic plants, genetic diversity is drastically reduced, resulting in an increased sensitivity of plants to diseases and the environment.

• Hormone Dependence: Most parthenocarpic fruits have to be induced with the spray of plant growth regulators, which is costly and may be hazardous to the environment.

• Limited Availability: Parthenocarpy occurs only in a few species or cultivars; therefore, seedless fruit supply is limited in the market.

MCQs on Parthenocarpy

Question 1: Which type of parthenocarpy requires pollination stimulus without the actual process of fertilization?

1. Vegetative parthenocarpy

2. Stimulative parthenocarpy

3. Both (a) and (b)

4. None of the above

Answer: The type of parthenocarpy that requires a pollination stimulus without actual fertilization is called stimulative parthenocarpy.

Fruit that forms without fertilization and has no seeds is known as parthenocarpy.
In stimulative parthenocarpy- fruit development is triggered by pollen (or a pollination stimulus) but fertilization does not take place. Usually, fruit kinds without seeds such as bananas and grapes exhibit this kind of parthenocarpy.
The plant produces growth hormones in response to the pollination stimulation which results in the formation of fruit, but since fertilization does not occur the fruit is seedless.

Hence, the correct answer is option 2)Stimulative parthenocarpy.

Question 2: Directions: In the following questions, a statement if Assertion (A) is followed by a statement of reason (R).

Assertion: Parthenocarpic fruits are fruits that develop without fertilization and are seedless.

Reason: Parthenocarpy can be induced by Auxin spray on fruits, e.g., tomatoes.

Mark the correct choice as

1. If both assertion and reason are true, and the reason is a correct explanation of assertion

2. If both assertion and reason are true, but the reason is not a correct explanation of assertion

3. If the assertion is true but the reason is false,

4. If both the assertion and the reason are false

Answer: Parthenocarpic fruits—

Fruits that develop without fertilization are called parthenocarpic fruits. Parthenocarpy can be induced through the application of growth hormones if favorable conditions are available (adequate moisture, oxygen, and suitable temperature they germinate, and such fruits are seedless. Banana is one such example.

Explanation: Parthenocarpic fruits are seedless, and spraying NAA on tomatoes can trigger parthenocarpy.

Hence, the correct option is 1) If both assertion and reason are true, and the reason is the correct explanation of the assertion

Question 3: Which hormones are commonly used to induce parthenocarpy?

1. Auxins and gibberellins

2. Cytokinins and abscisic acid

3. Ethylene and brassinosteroids

4. None of the above

Answer: Auxins and gibberellins are the hormones most frequently utilized to cause parthenocarpy, or the formation of fruit without fertilization.

Auxins: Without fertilization, these hormones encourage the growth of fruit.
Gibberellins: They also aid in promoting the growth of fruit, particularly in seedless types.
Plants can be treated with either of these hormones to create seedless fruits, like bananas or grapes.

Hence, the correct answer is option 1) Auxins and gibberellins

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