Cotyledons are an anatomical structure found in the embryo of a seed plant. Also referred to as seed leaves or scutellum, they are present within the seed and serve as the first leaves of the developing plant. Cotyledons play a crucial role in providing nutrients to the embryo before it begins photosynthesis and develops true leaves.
Typically, cotyledons are classified into two main types, based on their morphology and function: monocotyledons and dicotyledons. Monocotyledons, commonly referred to as monocots, possess a single cotyledon in their embryo. In contrast, dicotyledons, or dicots, have two cotyledons. These structures emerge from the embryo's axis upon germination and can vary significantly in shape and size depending on the plant species.
Cotyledons primarily act as energy reservoirs for the emerging plant, containing various nutrients, such as carbohydrates, proteins, and lipids, stored during the seed's development. They supply these reserves to the embryo, facilitating growth and development until the plant establishes its root system and begins producing its food through photosynthesis.
Furthermore, cotyledons also serve as protection for the delicate embryonic tissues within the seed. They shield the developing plant from external mechanical injuries, pathogens, and adverse environmental conditions, such as extreme temperatures or desiccation.
As the plant grows, cotyledons gradually wither and are eventually replaced by true leaves, which have a more complex structure and fulfill a different set of functions. Nonetheless, the initial role of cotyledons is vital for the successful germination and establishment of seed plants.
