Difference between Root and Stem
A typical flowering plant comprises a shoot system which remains above the ground and an underground root system. The shoot system, which originates from the plumule of the embryo in a seed, comprises stem, branches, leaves, flowers, and fruits with seeds. The root system, which originates from the radical of the embryo, develops into a primary root. Let us see how a stem differs from a root!
Stem:
The stem is the part of the plant which remains above the ground and arises from the plumule of the embryo present in a seed. A stem is generally green, at least when it is young and is differentiated into nodes and internodes. The buds, leaf, branches and bracts develop from the nodes.
A stem is generally positive phototropic (grows towards a source of light); negative hydrotropic (tends to move away from the water) and negatively geotropic (grows against the gravity). The stems generally have multicellular hairs that help prevent evaporation of water from its surface. Branches on a stem grow in a regular fashion from the axillary buds and they are exogenous, i.e. branches arise from outer layers.
Basic Functions of a Stem:
- It provides support to all aerial parts of a plant or tree like leaves, flowers, and connects them with the root system.
- It takes part in food production through photosynthesis.
- It transports water and minerals between roots and leaves through vascular system.
- It may store water, starch, sugar, etc.
- Some plants have a photosynthetic stem.
Root:
Root is the descending or underground part of a plant that arises from the radical of the embryo in a seed. However, it may also arise from any other part of a plant. It is generally non-green and lacks nodes and internodes. Roots are positively geotropic (grows towards gravity), positively hydrotropic (tends to grow towards the water), and may be neutral or negatively phototropic (grow away from a light source).
The tip of a root has a root cap which protects the root apical meristem as it penetrates the soil. The root hairs are always unicellular and are restricted to a specific area near the root tip. They help absorb water from the soil.
Basic functions of a root:
- It absorbs water and nutrients from the soil.
- It anchors the plant body to the ground and provides support to it.
- It stores food and nutrients.
- It helps in vegetative reproduction.
Based on the above information, some of the key differences between stem and root are as follows:
| Stem | Root |
|---|---|
| It arises from the plumule of the embryo present in the seed. | It develops from the radical of the embryo present in the seed. |
| The stem remains above the ground. It is the aerial part of the plant body. | It generally remains below the ground. It is the underground part of the plant body. |
| It is negatively hydrotropic, i.e. grows away from water. | It is positively hydrotropic, i.e. grows towards water. |
| It is negatively geotropic, i.e. grows away from the gravity. | It is positively geotropic, i.e. tends to grow towards gravity. |
| It is positively phototrophic, i.e. tends to grow towards the source of light. | It is neural or negatively phototrophic, i.e. tends to grow away from the source of the light. |
| It has nodes and internodes. | It lacks nodes and internodes. |
| It has axillary bud. | It lacks axillary bud. |
| Branches grow in a regular fashion from the axillary buds. | Branches grow in an irregular fashion behind the root tip. |
| Stem hairs do not occur at a specific region of the stem. | Root hairs are present at a specific region of the root near the root cap. |
| Stem hairs are multicellular and can be of various shapes and sizes. | Root hairs are unicellular and are tube-shaped. |
| Branches of the stem are exogenous, i.e. they arise from the outer layers. | Branches of the root are endogenous, i.e. they arise from the pericycle. |