What is the Difference Between Node and Internode

The main difference between node and internode is that the node is the point of attachment of leaves to the stem whereas the internode is the distance between two consecutive nodes. 

Node and internode are two structural parts found in the stem. The stem is one of the two structural parts of a vascular plant. Nodes bear axillary buds, which can either develop into branches, flowers or cones while an internode is responsible for the elongation of the stem.  

Key Areas Covered 

1. What is a Node
     – Definition, Features, Importance
2. What is an Internode
     – Definition, Features, Importance
3. What are the Similarities Between Node and Internode
     – Outline of Common Features
4. What is the Difference Between Node and Internode
     – Comparison of Key Differences

Key Terms 

Axillary Bud, Budding, Internode, Node, Stem Cutting, Transportation

What is a Node 

A node is the structural part of the stem of vascular plants, which forms a slight swelling in the stem. Nodes contain either scars or generative structures such as axillary buds, flower buds, or buds of cones. The axillary buds are responsible for the development of branches. Aerial roots also develop from some plant nodes.  

Figure 1: Nodes and Internodes

The identification of nodes is important for the vegetative propagation of plants. Most woody and herbaceous plants can be propagated through stem cutting. For successful rooting, a cut more than 6 inches in length should be taken from the mother plant. Also, pruning is a method used to maintain the size of the plant and when the stems are pruned above a node, the axillary bud of that node becomes induced and produce new stems. When budding, the node of one plant serves as the scion and it should be cut off with the cambium. 

What is an Internode 

Internode is the part of the stem that occurs between two consecutive nodes. The length of the internode provides a proper space between the two consecutive nodes. But, some plants such as dwarf conifers always have short internodes. Therefore, these plants can be pruned or sheared into different shapes.  

Figure 2: Adventitious Roots Emerging from Nodes

Furthermore, both xylem and phloem occur in the internode; therefore, the main function of internodes is transportation. The xylem is responsible for the transportation of water from the roots to the leaves while the phloem is responsible for the translocation of food from leaves to the storage parts. Other than that, the lengthening of the internodes increases the height of the plant. 

Similarities Between Node and Internode 

• Node and internode are two structures in the stem of a vascular plant. 
• Both have unique functions related to the stem. 

Difference Between Node and Internode 

Definition 

A node refers to the part of a plant stem from which one or more leaves emerge, often forming a slight swelling while an internode refers to the part of a plant stem between two of the consecutive nodes. Hence, this is the main difference between node and internode.

Axillary Bud 

Another difference between node and internode is that while nodes contain an axillary bud, internodes lack axillary buds. 

Function

There is also a difference between node and internode in their respective functions. Nodes bear buds which can develop into branches, flowers or cones while internodes are responsible for increasing the length of the stem. 

Conclusion 

A node is a slight swelling of the stem of a vascular plant characterized by the presence of a scar or axillary bud, which develops into a branch. Other than axillary buds, nodes may contain flower or cone buds. An internode is the part of the stem between two consecutive nodes. It is responsible for increasing the height of the plant. Therefore, the main difference between node and internode is the structure and the function.

Reference:

1. VANDERLINDEN, COLLEEN. “A Plant Node Is Where Stems Form Branches and Leaves.” The Spruce, TheSpruce, 5 Mar. 2018, Available Here

Image Courtesy:

1. “Plant nodes c” By Knulclunk at English Wikipedia – Transferred from en.wikipedia to Commons by Shupty. (Public Domain) via Commons Wikimedia  
2. “Polygonum amphibium (4973671699)” By Matt Lavin from Bozeman, Montana, USA – Polygonum amphibiumUploaded by Tim1357 (CC BY-SA 2.0) via Commons Wikimedia