Problem 92 - Objective Biology for NEET

Question

If fruit is developed without fertilization of the ovary, it is called (a) Parthenocarpic fruit (b) Apomictic fruit (c) Fleshly fruit (d) Polyembryonic fruit

Step-by-Step Solution

Answer

The correct answer is (a) Parthenocarpic fruit.

Step 1: Understanding the Types of Fruits

Let's start by understanding what each type of fruit means. Parthenocarpic fruits develop without fertilization of the ovary. Apomictic fruits develop from parts of the flower other than the ovary. Fleshy fruits have a soft texture, which usually derives from the ovary's walls. Polyembryonic fruits have multiple embryos in one seed.

Step 2: Matching the Definition with the Correct Term

The exercise asks what it's called when a fruit develops without fertilization of the ovary. According to the definitions we've established in Step 1, this describes Parthenocarpic fruit.

Key Concepts

Fruit Development

The process of fruit development is a fascinating journey that starts with a flower and ends with a ripe fruit. In angiosperms, or flowering plants, the mature ovary of a flower develops into a fruit after fertilization. During this phase, growth and differentiation take place, transforming the ovary into a structure that will either support seed development or serve to entice animals to disperse the seeds.

Once a flower is pollinated, and if fertilization is successful, the ovary undergoes physiological changes to become a fruit. However, in some cases, fruits may develop without fertilization, a phenomenon known as parthenocarpy. This process results in seedless fruits, and many commercially grown fruits like bananas and certain varieties of pineapples, oranges, and grapes are intentionally bred to be parthenocarpic for their lack of seeds and ease of consumption.

Parthenocarpic fruit development can be induced through genetic mutations or the application of plant hormones. It's a sought-after trait in agriculture to produce seedless fruits that are often more convenient for consumers.

Fertilization in Plants

Fertilization in plants occurs when the male gametes (pollen) from the anther of a flower reach the female gametes (ovules) housed within the ovary. This usually happens through the process of pollination, where pollen grains reach the stigma of a compatible flower. There are many vectors for pollination, including wind, water, and animals.

After pollination, a pollen tube grows, enabling the sperm cells to travel from the pollen grain down through the style to reach the ovules contained within the ovary. Once the sperm cells reach the ovules, they fuse with the egg cells to form a zygote. This is the pivotal moment of fertilization. The zygote then develops into an embryo, which will grow into a seed.

Each seed has the potential to grow into a new plant, making fertilization a central aspect of plant reproduction and biodiversity. The result, in most cases, is the development of a fruit which houses and protects the seeds, aiding in their dispersal.

Types of Fruits

Fruits come in an array of types and classifications, mainly based on the structure of the ovary and the way the seeds are enclosed within the fruit. Simple fruits develop from a single ovary, while aggregate fruits arise from several ovaries that were in the same flower. Conversely, multiple fruits form from the ovaries of many flowers growing in a cluster or inflorescence.

Besides their structural differences, fruits are commonly categorized by their texture: fleshy fruits, like tomatoes and berries, have a soft edible part, while dry fruits, such as nuts and legumes, lack this succulence. A unique class of fruits, known as parthenocarpic, develop without fertilization and seed formation. This gives rise to seedless varieties that are especially prized in the food industry.

Another interesting type is apomictic fruits, which reproduce asexually through a mechanism that bypasses the normal sexual modes of reproduction. Unlike parthenocarpic fruits, some apomictic fruits may still contain seeds, but these seeds are genetically identical to the parent. Understanding these different types of fruits can aid in the comprehension of plant biology and the ways in which various fruit characteristics have been shaped by evolutionary pressures and human cultivation.