The key difference between root and shoot apical meristem is that root apical meristem is a small region at the tip of a root which consists of cells that are capable of dividing and giving rise to primary root tissues while shoot apical meristem is a region at the tip of all branches and stems which consists of cells rapidly divide and give rise to organs such as leaves and flowers.
Plants continue to grow and develop throughout their life span. Apical meristem is the region of cells which is capable of division and growth. Apical meristems are responsible for the extension of roots and shoots. The cells of apical meristem are small and spherical in shape. These cells rapidly divide by mitosis before differentiating into specific cell types. There are two types of apical meristems in plants: root apical meristem and shoot apical meristem. They are mainly found in the root and shoot tips. Root apical meristem provides cells for new roots. Shoot apical meristem produces leaves and flowers, etc.
CONTENTS
1. Overview and Key Difference
2. What is Root Apical Meristem
3. What is Shoot Apical Meristem
4. Similarities Between Root and Shoot Apical Meristem
5. Side by Side Comparison – Root vs Shoot Apical Meristem in Tabular Form
6. Summary
What is Root Apical Meristem?
Root apical meristem is the small region at the tip of a root which is actively growing. It consists of cells that are rapidly dividing and providing new cells for future roots. Root apical meristem is cup-shaped, and it is protected by a root cap. Cells are continuously sloughed off the outer surface of the root cap.
Figure 01: Root Apical Meristem
Root apical meristem is relatively a short region which shows positive geotropism. It has an inactive centre called the quiescent centre. The quiescent centre maintains the surrounding stem cells by preventing their differentiation. It can also act as a reservoir of stem cells to replenish lost or damaged cells.
What is Shoot Apical Meristem?
Shoot apical meristem is a region at the tip of all branches and stems of higher vascular plants. It consists of rapidly dividing and undifferentiated cells. Shoot apical meristem is terminal, and it is protected by a crown of young leaves. It is dome-shaped and has leaf primordia.
Figure 02: Shoot Apical Meristem
Moreover, shoot apical meristem gives rise to organs such as leaves, new buds and flowers. Therefore, shoot apical meristems are the centres that form the primary plant body.
What are the Similarities Between Root and Shoot Apical Meristem?
- Root and shoot apical meristems are found at the tips or growing apex of roots and shoots in plants, respectively.
- They are primary tissues.
- The cells of the shoot and root apical meristems divide rapidly.
- Moreover, they are indeterminate or undifferentiated cells.
What is the Difference Between Root and Shoot Apical Meristem?
The key difference between root and shoot apical meristem is that root apical meristem provides the meristematic cells for the future root growth while shoot apical meristem gives rise to organs such as leaves and flowers, etc. Furthermore, the root apical meristem is positively geotropic while the shoot apical meristem is positively phototrophic. Moreover, there is a quiescent centre in root apical meristem while shoot apical meristem does not have this centre.
The below infographic tabulates the differences between root and shoot apical meristem in more detail.
Summary – Root vs Shoot Apical Meristem
In plants, apex region of roots has root apical meristem while apex region of the shoot has shoot apical meristem. Apical meristems are the regions composed of rapidly dividing and indeterminate or undifferentiated cells. Root apical meristem cells divide mitotically and provide cells for new roots. Shoot apical meristem cells divide and produce organs such as flowers and leaves. Root apical meristem shows positive geotropism and negative phototropism. Shoot apical meristem shows positive phototropism and negative geotropism. A crown of young leaves protects the shoot apical meristem while a root cap protects the root apical meristem. Thus, this summarizes the difference between root and shoot apical meristem.
Reference:
1. “Apical Meristem.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.
2. “Meristem.” Wikipedia, Wikimedia Foundation, 29 Oct. 2020, Available here.
Image Courtesy:
1. “Figure 25 01 03” By CNX OpenStax – (CC BY 4.0) via Commons Wikimedia
2. “Coleus stemtip L” By Jon Houseman – Jon Houseman and Matthew Ford (CC BY-SA 4.0) via Commons Wikimedia