Cotyledons as a Source of Food for Seedlings

Introduction:
Seedlings are young plants that emerge from seeds. They require a source of food to support their growth and development until they can produce their own food through photosynthesis. The food reserves for seedlings are stored in various parts of the seed, one of which is the cotyledon.

Definition of Cotyledon:
Cotyledons are embryonic leaves found in the seeds of flowering plants. They can vary in number, with some seeds having one cotyledon (monocots) and others having two cotyledons (dicots). Cotyledons play a crucial role in the early development of the seedling.

Function of Cotyledons:
Cotyledons serve as a source of food for the seedling before it can make its own food through photosynthesis. They contain stored nutrients, such as carbohydrates, proteins, and fats, which are necessary for the seedling's growth and development.

Utilization of Cotyledon Reserves:
When a seed germinates, the cotyledons absorb water and swell. Enzymes are then activated, which break down the stored nutrients in the cotyledons into simpler forms that can be utilized by the seedling. These nutrients are transported to the growing regions of the seedling, including the shoot and root, where they are used for energy and building new tissues.

Duration of Cotyledon Utilization:
The cotyledons continue to provide nourishment to the seedling until it is capable of producing its own food through photosynthesis. This usually occurs when the seedling develops true leaves, which are different from the cotyledons and are specialized for photosynthesis. At this point, the seedling becomes independent and no longer relies on the cotyledon for food.

Conclusion:
In conclusion, the correct answer to the question is option 'C' - cotyledon. The cotyledons in a seed serve as a source of food for the developing seedling until it can produce its own food through photosynthesis. They contain stored nutrients that are broken down and utilized by the seedling for growth and development.