Question

Describe the epigeal and hypogeal germination. Give the main difference between the two types of germination.

Answer 1

Epigeal Germination:	Hypogeal Germination:
In this type of seed germination, the cotyledons come out of the soil, e.g., Castor.	The cotyledons remain inside the soil (e.g. Pea).
The cotyledons are brought out of the soil by the excessive growth of the hypocotyl.	The hypocotyl does not elongate much. Instead, the epicotyl grows and takes the plumule above the soil.
The terminal region of the hypocotyl is curved to protect the plumule and cotyledons from the friction of the soil.	The terminal part of the epicotyl is curved in order to reduce damage to plumule by friction from soil particles.
The plumule remains enclosed and protected by cotyledons till it comes out of the soil.	There is no such provision
The cotyledons become green and function as the first leaves of the seedling.	The cotyledons do not take part in photosynthesis.

1. Hypogeal germination implies that the cotyledons stay below the ground. The epicotyl (part of the stem above the cotyledon) grows, while the hypocotyl (part of the stem below the cotyledon) stays the same length. In this way, the epicotyl pushes the plumule above the ground.
   
2. Epigeal germination is a botanical term indicating that the germination of a plant takes place above the ground. An example of a plant with epigeal germination is the common bean.