What is the primary function of cotyledons in a seed?

Cotyledons are essential components of seeds that serve primarily to store and transfer nutrients to the developing embryo. They act as a food supply for the young plant before it can begin the process of photosynthesis or develop its own root system to absorb nutrients from the soil.

In many plants, cotyledons contain stored starches, proteins, and oils, which are critical for the growth of the embryo during germination. Once the seed has germinated and the true leaves appear, the plant will then begin to use sunlight to create its own food through photosynthesis. Until that point, the cotyledons support the initial stages of growth by providing the necessary energy and nutrients.

While they may play a minor role in some other functions related to seed development, such as appearing in different forms depending on the plant species, the primary role remains nutrient storage and the transfer of these vital resources to support the embryo's growth.