Read the passage and answer the following questions.
In the process of sexual reproduction in angiosperms, the seed serves as the final product. It is formed from a fertilised ovule and is typically enclosed within a fruit. A seed is composed of several parts, including seed coats, cotyledons, and an embryo axis. The cotyledons of the embryo are simple structures that are often thick and swollen, storing food reserves, particularly in legumes. Mature seeds may be albuminous (retaining a part of the endosperm) or non-albuminous (with no residual endosperm). The integuments of the ovules harden to become protective seed coats, and a small pore called the micropyle remains, enabling the entry of oxygen and water during seed germination. As the ovules develop into seeds, the ovary undergoes transformation into a fruit. This simultaneous process involves the ovules turning into seeds, and the ovary walls developing into the fruit's pericarp. Fruits come in different types, including fleshy fruits like guava, orange, and mango, as well as dry fruits such as groundnut and mustard. Many fruits have evolved mechanisms for the dispersal of seeds.
The number of seeds in a fruit depends on the number of ovules in the ovary. In which of the following pairs would both plants be expected to bear single-seeded fruits?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Wheat and mango
Each ovule that is fertilised becomes one seed, so the number of ovules in an ovary decides the largest number of seeds a fruit can have. The number of ovules in an ovary may be one (wheat, paddy, mango) or many (papaya, water melon, orchids). A single-seeded fruit is expected only where the ovary has one ovule.
Option (1) Papaya and mango — Incorrect. Mango has one ovule in its ovary, but papaya has many ovules, and its fruit carries many seeds.
Option (2) Wheat and mango — Correct. Both wheat and mango have a single ovule in the ovary, so each fruit holds one seed.
Option (3) Water melon and paddy — Incorrect. Paddy has one ovule, but water melon has many ovules and its fruit has many seeds.
Option (4) Orchid and wheat — Incorrect. Wheat has one ovule, but orchids have many. In fact, each orchid fruit contains thousands of tiny seeds.
Note: Two plant lists in brackets, one ovule against many, quietly made this whole question. The examples NCERT tucks inside brackets are worth reading as closely as the sentence around them.
NCERT Extract:
The Pistil, Megasporangium (Ovule) and Embryo Sac – “… Arising from the placenta are the megasporangia, commonly called ovules. The number of ovules in an ovary may be one (wheat, paddy, mango) to many (papaya, water melon, orchids).”
Seed – “… Can you think of some plants in which fruits contain very large number of seeds. Orchid fruits are one such category and each fruit contain thousands of tiny seeds. Similar is the case in fruits of some parasitic species such as Orobanche and Striga.”