Short Notes on Structure of Mature Seed

Structure of Mature Seed:

      After double fertilization ovule develops into seeds. During the last stages of seed maturation the water is lost by dehydration. The mature seed contain 5% to 15% water by weight. The embryo stops growing and developing until the seed germinates. Embryo is surrounded by cotyledons (Seed leaf) or endosperm or by both.

      Both endosperm and embryo are enclosed in seed coat, which is formed by ovule integument. If a seed has single cotyledon it is known as monocot. The embryo is in the form of axis. The part of embryo above the cotyledons is called epicotyl. At the tip of epicotyl there is plumule, which will develop into shoot. The part of embryo below the cotyledons is called hypocotyl. It has redicles at its tips, which will develop into roots. The seed of monocot has single cotyledon e.g. corn, wheat, rice and other member of grass family. The cotyledon is shield like and is called scutellum, it absorbs nutrients from endosperm during germination. The embryo of grass seed is enclosed by two sheaths. The sheath covering the roots is called colerhiza. The shoot is covered by coleoptile.