Definition - What does Seed leaf mean?
A seed leaf, or cotyledon, is the embryonic leaf formed by a seedling. It may remain in the ground when the seed germinates, or it could form a pair of initial proto-leaves that help provide photosynthesis during early life.
MaximumYield explains Seed leaf
A seed leaf is precisely what it sounds like – a leaf that forms within the seed, before germination. After germination, the leaf may stay below in the ground, where it will provide nutrition for the growing plant. However, it may form part of a pair of proto-leaves and provide photosynthesis for the seedling while it develops its first true leaves.
Seed leaves are not considered true leaves for several reasons. Primarily, it is because they are part of the embryonic plant, and are not formed by the seedling itself. They act as a nutrient store for the seedling, much like the yolk sac in an egg supports the growth and development of an embryonic bird.
Most seed leaves that remain on the seedling as it grows look almost identical, regardless of the type of plant. They are narrow, long leaves in pairs, that originally appear at the top of the plant. As the plant grows, its first pair of true leaves will form above the seed leaves, which will eventually die and fall away as the true leaves become larger.
The presence and type of seed leaf is also important in determining the classification of the plant that will grow. For instance, monocots have only a single seed leaf, which often stays in the ground. Dicots, on the other hand, have a pair of seed leaves that usually appear at the top of the growing stem and are then replaced during growth.