DISTINGUISH BETWEEN THE EUDICOT STEM AND MONOCOT STEM
The eudicot stem and monocot stem are two types of stems found in flowering plants.
Eudicot Stem:
1. The eudicot stem has a vascular cambium that gives rise to secondary growth.
2. The arrangement of vascular bundles is in a ring-like formation.
3. The pith is well-developed, and the cortex is distinguishable.
4. The stem is usually woody and has distinct trees and shrubs.
5. The stem of most eudicots shows a secondary growth in thickness.
6. Eudicot stem exhibits collateral vascular bundles, containing phloem on the outer side and xylem on the inner side.
Monocot Stem:
1. The monocot stem does not undergo secondary growth.
2. The vascular tissue bundles are scattered across the stem without any definite arrangement.
3. The pith is usually less well-developed, and it is challenging to distinguish cortex from outer tissues.
4. The stem is mostly herbaceous and lacks distinct trees and shrubs.
5. Monocot stem grows and elongates with the help of the intercalary meristem.
6. The vascular bundles in monocots are considered to be conjoined and scattered within the ground tissue matrix.
The main differences between the stem structures of eudicots and monocots are:
1. Vascular Bundles Arrangement:
- Eudicot stem: The vascular bundles in eudicot stems are arranged in a ring or cylinder-like pattern. The bundles are arranged in a radial or circular manner in the stem, forming distinct layers.
- Monocot stem: In monocot stems, the vascular bundles are scattered throughout the stem tissue. They are not arranged in a ring-like structure but are dispersed randomly.
2. Secondary Growth:
- Eudicot stem: Eudicot stems have the ability to undergo secondary growth, meaning they can increase in girth over time. This is accomplished through the activity of a lateral meristem called the vascular cambium, which adds new layers of secondary xylem (wood) and secondary phloem (inner bark) to the stem.
- Monocot stem: Monocot stems lack a vascular cambium and, therefore, do not undergo secondary growth. As a result, they do not produce wood and remain herbaceous.
3. Pith:
- Eudicot stem: Eudicot stems have a distinct pith in the center. The pith is a region of parenchyma cells that are located in the core of the stem.
- Monocot stem: Monocot stems lack a well-developed pith. The central region of the stem is typically occupied by parenchyma cells or scattered vascular bundles.
4. Epidermis:
- Eudicot stem: The epidermis of eudicot stems usually consists of a single layer of cells covered by a waxy cuticle. In some cases, the epidermis may have stomata, which are small openings that allow for gas exchange.
- Monocot stem: The epidermis of monocot stems also consists of a single layer of cells covered by a cuticle. However, monocots typically lack stomata in their stems.
5. Cortex:
- Eudicot stem: The cortex of eudicot stems is usually relatively wide and consists of parenchyma cells. It functions as a storage tissue for nutrients and water.
- Monocot stem: The cortex in monocot stems is usually narrow and composed of parenchyma cells. It also functions in nutrient storage but may be less pronounced than in eudicots.
It's important to note that while these characteristics describe typical patterns, there can be exceptions and variations within each group of plants.