Difference Between Stem and Root

A typical flowering plant has an aerial shoot system and an underground root system. 

The shoot stem originates from plumule of the embryo. It consists of stem, branches, leaves, flowers, fruits and seeds. 

The root system originates from the radicle of the embryo. The radicle develops into a primary root. Root originating from parts other than radicle called adventitious roots.
 

Stem vs Root

Stem	Root
It develops from plumule.	It develops from radicle.
Stem does not develop from other than the plumule. Sometimes adventitious buds develop from the different parts of the plant body.	Root may develop from any portion of the plant body in addition to the radicle. These are called adventitious roots.
Stem is the aerial part of the plant body.	Root is the underground part of the plant body.
Stem is negatively hydrotropic i.e. moves away from water.	Root is positively hydrotropic i.e. moves towards water.
Stem is negatively geotrophic i.e. Grows against the force of gravity.	Roots is positively geotrophic i.e. grows towards the force of gravity.
Stem is generally green in colour	Roots is generally colourless
Stem elongates with the help of apical bud.	Roots grows or elongates with the help of apical meristem.
Stem is with nodes and internodes.	Root is without nodes and internodes.
Stem bears leaf, bud, flower and fruit.	Root does not bear leaf, bud, flower and fruit.
Axillary bud is present.	Axillary bud is absent.
Terminal bud is present.	Terminal bud is absent.
Cap absent at the tip.	Terminal root cap is present.
Branches grow in a regular fashion and always by the development of axillary bud.	Branches grow in an irregular fashion.
Branches develop near the tip.	Branches develop behind the tip.
Stem hairs are present but it has no definite region of occurrence.	Root hairs are present at a particular region of the root.
Stem hair are multicellular and they are of various sizes and shapes.	Root hair is unicellular and they are tube like.
Branches are exogenous i.e. They arise from the outer layers.	Branches are endogenous  i.e. they arise from the pericyle.
Functions : It bears branches, leaves, flowers and fruits It absorbs carbon dioxide gas and oxygen through the stomata present on leaf surfaces. It can synthesise carbohydrate food by photosynthesis. It stores very little food.	Functions It fixes firmly the plant within the soil and acts as anchorage. It absorbs water and mineral nutrients from the soil. with the help of root hairs. It cannot synthesise food. It sores excess food.