Difference Between Cotyledon and Endosperm

Cotyledon vs Endosperm
 

Cotyledon and endosperm are two types of tissues found in the embryo of flowering plants. They are important in absorbing and storing nutrients in plant embryos during seed germination. There are many different features exist in these tissues, present in both dicot and monocot.

What is Cotyledon?

Cotyledon is a seed leaf found in embryos of flowering plants. Cotyledon found in monocots is important in food absorption whereas, in dicots, cotyledon’s functions are in both absorption and storage of food. Generally, monocot embryos contain one cotyledon and dicot embryos contain two; however, there are exceptions. Embryos that lack cotyledons are referred to as acotyledonous. Furthermore, there are dicots with only one cotyledon, known as monocotylar or monocotyledonous dicots. Dicots that appear to have one cotyledon due to the fusion of two cotyledons are called preudomonocotyledounous. In some occasions, in dicots, embryo develops more than the normal two cotyledons; it is a condition called schizocotyly while, in gymnosperms, the same condition is known as polycotyledony.

Cotyledons vary widely in size, shape and functions. For example, thick and fleshy cotyledons may serve as a nutrient source, while thin, leaf-like cotyledons may serve as photosynthetic organ during seed germination.

What is Endosperm?

Endosperm is the most common storage tissue in the seed of angiosperms, which originates from the union of a male nucleus and the polar nuclei of embryo sac. The numbers of nuclei that fuse in the central cell determine the ploidy of endosperm. This tissue is completely digested or near so, by growing sporophyte during the embryo development. Therefore, in most mature embryos, endosperm appears to be absent. Usually it persists in mature seeds of monocots while it is absent in mature seeds of dicots. There are three basic types of endosperms exist in floral crops; namely, cellular, nuclear, and helobial.

What is the difference between Cotyledon and Endosperm?

• In monocots, cotyledon is important in food absorption, whereas endosperm serves as a food storage tissue.

• Usually, in mature seeds of dicots, cotyledon is present while endosperm is absent.

• Endosperm, unlike the cotyledon, originates by the union of male nuclei and polar nuclei of embryo sac.

• In dicots, endosperm is digested completely before the seed germinates, whereas cotyledon remains until the seedling is capable of photosynthesis.

• In dicots, cotyledon completely absorbs the food stored in endosperm.

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