Monocot stem does not undergo secondary thickening while dicot stem undergoes secondary thickening. This is the key difference between monocot and dicot stem.
Monocot plants and dicots plants possess many differences both structurally and functionally. The leaf structure, the stem structure and the root structure of monocots plants and dicot plants possess many differences.
CONTENTS
1. Overview and Key Difference
2. What is a Monocot Stem
3. What is a Dicot Stem
4. Similarities Between Monocot and Dicot Stem
5. Side by Side Comparison – Monocot vs Dicot Stem in Tabular Form
6. Summary
What is a Monocot Stem?
A monocotyledonous (monocot) plant stem is the stem of a monocot plant that contains only one cotyledon in the seed. It contains many unique characteristics. The stem is typically circular with small depressions since lateral branches are present.
Figure 01: Monocot Stem
Monocot stems possess a thick cuticle and a single layered epidermis. They do not possess any epidermal hairs. The monocot stem does not contain a distinct endodermis and a pericycle. They have a sclerenchymatous hypodermis. The epidermis contains silica depositions.
What is a Dicot Stem?
The dicotyledonous (dicot) plant stem is the stem of dicot plants that contains two cotyledons in the seed. Similar to monocot stem, the dicot stem also contains different unique characteristics like including a thick cuticle. Furthermore, they possess a well defined epidermis and numerous epidermal hairs.
Figure 02: Dicot Stem
The hypodermis is collenchymatous. Dicot plants possess a limited number of vascular bundles ranging from 4-8. Bundle sheath does not surround the vascular bundles. Another feature is the ground tissue of dicot plants differentiates into stellar and extra stellar tissues.
What are the Similarities Between Monocot and Dicot Stem?
- Both monocot and dicot stems are circular.
- Single cell layered epidermis is present in both monocot and dicot stems.
- Both stems possess a thick cuticle.
- The monocot and dicot stems possess a hypodermis.
- Both monocot and dicot stems possess organised xylem and phloem vascular bundles.
- In both monocot and dicot stems, vascular bundles are conjoint and collateral.
What is the Difference Between Monocot and Dicot Stem?
Monocot vs Dicot Stem |
|
| A monocotyledonous (monocot) plant stem is the stem of monocot plants that contains only one cotyledon in the seed. | The dicotyledonous (dicot) plant stem is the stem of dicot plants that contains two cotyledons in the seed. |
| Epidermal Hairs | |
| No epidermal hairs are present in monocot stem. | Multicellular epidermal hairs are present in dicot stem. |
| Hypodermis | |
| Sclerenchymatous hypodermis is present in monocot stem. | Collenchymatous hypodermis is present in dicot stem. |
| Endodermis | |
| Endodermis is absent in monocot stem. | Endodermis is present in dicot stem. |
| Protoxylem | |
| No protoxylem elements in monocot stem. | In dicot stem, many protoxylem elements are present. |
| Metaxylem | |
| Only two metaxylem elements are present in monocot stem. | Many metaxylem elements are present in dicot stem. |
| Xylem Elements | |
| Structure of the xylem elements is circular in monocot stem. | Structure of the xylem elements is polygonal in dicot stem. |
| Protoxylem Lacuna | |
| Protoxylem lacuna is present in monocot stem. | No protoxylem lacuna is present in dicot stem. |
| Bundle Cap | |
| A bundle cap is present around the vascular bundle of monocot stem. | Bundle cap is not there in dicot stem. |
| Bundle Sheath | |
| Bundle sheath surrounds the vascular bundles in monocot stem. | Bundle sheath does not surround vascular bundles in dicot stem. |
| Pericycle | |
| No pericycle is found in monocot stem. | Pericycle is present in dicot stem. |
| Number of Vascular Bundles | |
| Numerous vascular bundles are present in monocot stem. | 4-8 vascular bundles are present in dicot stem. |
| Arrangement of Vascular Bundles | |
| Arrangement of vascular bundles is conjoint, collateral and close in monocot stem. | Arrangement of vascular bundles are conjoint, collateral and open in dicot stem. |
| Phloem Fibers | |
| Phloem fibers are absent in monocot stem. | In dicot stem phloem fibers are present. |
| Phloem Parenchyma | |
| No phloem parenchyma are present in monocot stem. | Phloem parenchyma is present in dicot stem. |
| Pith | |
| Pith is absent in monocot stem. | Pith is present in dicot stem. |
| Medullary Rays | |
| Medullary rays are absent in monocot stem. | Medullary rays are present in dicot stem. |
| Secondary Thickening | |
| Monocot stem does not undergo secondary thickening. | Dicot stem undergoes secondary thickening. |
| Deposition of Silica | |
| There is silica deposited over the epidermis of the monocot stem. | There is no silica deposition in the dicot stem. |
| Differentiation of Ground Tissue | |
| Ground tissue does not differentiate into stellar and extra stellar tissues in monocot stem. | Ground tissue is differentiated into stellar and extra stellar tissues in dicot stem. |
Summary – Monocot vs Dicot Stem
Plants are differentiated into monocots and dicots according to the number of cotyledons present in the seed. The stems of monocot and dicots possess similar characteristics but have many differences too. Out of the many important differences between monocot and dicot stem, the key difference between monocot and dicot stem is that the monocots do not undergo secondary thickening while dicots do. However, both types possess a thick cuticle.
Reference:
1.“Monocot Stem.” Monocot Stem | Sciencetopia. Available here
2.“Easy Biology Class.” Easybiologyclass. Available here
3.“Dicot Stem.” Dicot Stem | Sciencetopia. Available here
Image Courtesy:
1.’Botana curus monocot stem 40×’By Kelvinsong – Own work, (CC BY 3.0) via Commons Wikimedia
2.’36316873923’by Berkshire Community College Bioscience Image Library (Public Domain) via Flickr