Difference Between Stem and Trunk

The key difference between stem and trunk is that the stem usually refers to the main structural axis of a plant while trunk usually refers to the main structural axis of a tree.

Stem and trunk are two botanical names sometimes used in a similar sense. Strictly speaking, there is some difference between stem and trunk. The experts in botany or plant biology and plant biotechnology say that a trunk is not only a stem, but it is the main stem of a tree. From this explanation, we understand that what is stem to a plant is the trunk to a tree. Hence, it can be said that the word ‘trunk’ is used while referring to a tree whereas the word ‘stem’ is used while referring to a plant.

CONTENTS

1. Overview and Key Difference
2. What is Stem
3. What is Trunk
4. Similarities Between Stem and Trunk
5. Side by Side Comparison – Stem vs Trunk in Tabular Form
6. Summary

What is Trunk?

Tree is simply a plant that belongs to Kingdom Plantae. However, the usage of the word ‘tree’ limits to refer a woody perennial plant which has a single trunk and grows to a specific height. Trunk of a tree is an important structure which facilitates the easy differentiation of a tree from other plants. Hence, the trunk usually refers to the main wooden axis of a tree. Bole is a synonym of the trunk. The trunk actually supports the branches of the tree (crown) and is in turn supported by the roots. It is interesting to note that the trunk of a tree is directly attached to the roots of the tree. Furthermore, trunk of a tree provides a shape to the tree as well as it strengths the tree. All the tubes that transport water, minerals and nutrients from roots to leaves travel within the trunk of the tree.

Structurally, trunk has five main parts; namely, bark, inner bark, cambium, sapwood and heartwood. The bark is the protective layer of the trunk while the inner bark consists of the phloem. Sapwood consists of the xylem while the heartwood consists of old xylem cells and it is the centre of the trunk.

Due to the secondary growth of plants, trunk becomes thick over time. Ultimately it becomes the most important part of a tree which used in timber production. Furthermore, trunk has many applications such as paper industry, furniture making, constructing buildings, etc.

What is Stem?

A stem is one of the two main structural axes of a vascular plant. Unlike the trunk of a tree, stem is not necessarily protected with a bark; hence, does not form part of the bark. It consists of nodes and internodes. Structurally, there are three main parts of a stem; namely, phloem, cambium, and xylem. Often the stem is a green straw-like structure present under the actual flower of the plant. It is important to know that leaves may stick out of the stem.

In some plants, stems can be found below the ground in the form of tubers, rhizomes and corms. Other than storing foods, some stems store water while the green stems carry out photosynthesis. In addition, some plant stems are edible and hence, humans and other animals consume them. A stem has different functions in a plant. It supports leaves, buds, flowers and fruits. Furthermore, it helps to transport nutrients, and water to other parts of the plant.

What are the Similarities Between Stem and Trunk?

• Both stem and trunk are main structural axes of plants.
• They provide strength to plants.
• Furthermore, they support branches of the plants.
• Also, they facilitate the transportation of water and nutrients.

What is the Difference Between Stem and Trunk?

Stem and trunk are two words often used interchangeably. But there is a difference between stem and trunk. Stem refers to one of the main structural axes of a plant while trunk refers to the main structure of a tree. Another difference between stem and trunk is that stems can photosynthesize while most trunks cannot. Furthermore, stem store water and foods, unlike trunks.

Shown below is the comparison summary of the difference between stem and trunk.

Summary – Stem vs Trunk

Stem and trunk are two terms that refer structurally similar part of a plant. But their use differs based on the type of the plant. Tree is simply a plant, but it is a woody perennial plant which grows into a certain height. Tree has the trunk. Trunk is the main structure of a tree that supports its crown. On the other hand, stem is one of the two main axes of a vascular plant. In summary, above is the key difference between stem and trunk.

Reference:

1.Britannica, The Editors of Encyclopaedia. “Stem.” Encyclopædia Britannica, Encyclopædia 2.Britannica, Inc., 16 May 2018. Available here

Image Courtesy:

1.”mossy, tree, trunk” (CC0) via pixnio
2.”Plant Rose Stem Sharp Thorn Rose Prickle Stem” (CC0) via Max Pixel