The fruit which develops without fertilisation is called:
(b) Parthenocarpic fruit
Understanding Fruit Development Without Fertilisation
The question asks about the type of fruit that develops without the process of fertilisation. Fertilisation in plants typically involves the fusion of male and female gametes, which is a crucial step in the sexual reproduction process leading to seed and fruit formation.
What is Parthenocarpic Fruit Development?
Normally, fruit develops from the ovary of a flower after fertilisation. The seeds inside the fruit are also formed as a result of fertilisation. However, some plants can produce fruits even without fertilisation. This phenomenon is known as parthenocarpy, and the resulting fruits are called parthenocarpic fruits.
These fruits are typically seedless or contain non-viable seeds because the seed development process, which is initiated by fertilisation, does not occur. Examples of naturally occurring parthenocarpic fruits include some varieties of bananas, pineapples, and figs. Parthenocarpy can also be induced artificially using plant hormones.
Examining the Options
- (a) True fruit: A true fruit develops solely from the ovary after fertilisation. Examples include mango, tomato, and pea. This is the standard mode of fruit development through sexual reproduction. Since the question specifies development *without* fertilisation, this option is incorrect.
- (b) Parthenocarpic fruit: This term specifically refers to a fruit that develops from the ovary without the process of fertilisation. This development results in seedless fruits. This definition perfectly matches the condition described in the question.
- (c) False fruit: A false fruit, also known as a pseudocarp, is a fruit in which parts of the flower other than the ovary develop into the fruit. Structures like the thalamus, calyx, or petals contribute to the fruit structure. Examples include apple (thalamus), strawberry (thalamus), and cashew (pedicel). While false fruits involve structures other than the ovary, their formation may or may not involve fertilisation of the ovules within the ovary (which develops into the actual seeds). The key feature is the involvement of non-ovary parts, not the absence of fertilisation for the ovary itself. Therefore, this is not the correct answer to the question as posed.
- (d) Polyembryonic fruit: Polyembryony is a condition where a single seed contains more than one embryo. This phenomenon occurs within the seed itself, not related to how the fruit develops from the flower. It is common in plants like citrus and mango. This term describes the seed content, not the method of fruit development relative to fertilisation. Thus, this option is incorrect.
Conclusion
Based on the definitions, a fruit that develops without fertilisation is correctly termed a parthenocarpic fruit. This process leads to seedless fruits.
Parthenocarpic Fruit Development Explained
Parthenocarpy can happen naturally in some plants or be induced artificially. Natural parthenocarpy can be genetic, environmental (e.g., frost or specific temperatures), or hormonal. Artificial parthenocarpy is often achieved by applying plant growth regulators like auxins or gibberellins to the flowers, which stimulates ovary development into a fruit even without pollination and fertilisation.
| Fruit Type | Development Origin | Fertilisation Required? | Seed Presence | Example |
|---|---|---|---|---|
| True Fruit | Ovary | Yes | Present (typically) | Mango, Tomato |
| Parthenocarpic Fruit | Ovary | No | Absent or non-viable | Banana, Seedless Grapes |
| False Fruit (Pseudocarp) | Ovary + other floral parts (e.g., thalamus, calyx) | May or may not be required for seed development in ovary part | Present (in seed-bearing part) | Apple, Strawberry |
Revision Table: Fruit Types and Development
Reviewing the different types of fruit development helps distinguish between them clearly.
| Term | Key Feature | Relation to Fertilisation |
|---|---|---|
| True Fruit | Develops only from the ovary. | Develops AFTER fertilisation. |
| Parthenocarpic Fruit | Develops from the ovary. | Develops WITHOUT fertilisation. |
| False Fruit | Develops from the ovary PLUS other floral parts. | Fertilisation may or may not occur for seed development in the ovary part. |
| Polyembryonic Fruit | Fruit containing seeds with multiple embryos. | Relates to seed development, not fruit development method regarding fertilisation. |
Additional Information on Parthenocarpy and Fruit Development
Parthenocarpy is an important trait in horticulture, especially for fruits where seeds are undesirable (like seedless grapes or watermelons). It can occur naturally through mutations or be induced for commercial purposes.
- Natural Parthenocarpy: Found in certain varieties of plants like banana, pineapple, some citrus fruits, and figs.
- Induced Parthenocarpy: Can be caused by applying plant growth hormones (auxins, gibberellins) or through specific breeding techniques or genetic modifications.
- Significance: Parthenocarpic fruits are valuable to consumers because they are seedless. They also ensure fruit set in conditions where pollination or fertilisation might be difficult or absent, such as in greenhouses or adverse weather conditions.
Important Questions from Sexual Reproduction in Flowering Plants
In a velvet grass seed, the cotyledon is called:
Which of the following is not a cannabinoid?
Arrange the following stages of primary succession in water in the correct sequence:
A. Rooted submerged plants
B. Marsh meadows
C. Phytoplanktons
D. Scrubs followed by trees
E. Free-floating plants
Choose the correct answer from the options given below:
Arrange the following steps of Polymerase Chain Reaction in correct sequence:
A. Annealing of Primer
B. Denaturation of dsDNA
C. Extension of Primer
D. Amplification
Choose the correct answer from the options given below:
Identify the gas which was not used by Miller in his classic experiment:
