Main Difference – Meristematic Tissue vs Ground Tissue
Meristematic tissue and ground tissue are two types of tissues found in plants. The main difference between meristematic tissue and ground tissue is that the cells in the meristematic tissue are capable of continuously dividing whereas ground tissue is a type of a permanent tissue whose cells are incapable of dividing. Meristematic tissue is composed of parenchyma cells. Ground tissue is composed of parenchyma, collenchyma, and sclerenchyma cells. Meristematic tissue can be found in the tips of the shoots and roots, and buds. It is also found in woody plants as a ring around the stem. Ground tissue can be found in between the dermal and the vascular regions of the stem, roots, and leaves.
Key Areas Covered
1. What is Meristematic Tissue
– Definition, Characteristics, Function
2. What is Ground Tissue
– Definition, Characteristics, function
3. What are the Similarities Between Meristematic Tissue and Ground Tissue
– Outline of Common Features
4. What is the Difference Between Meristematic Tissue and Ground Tissue
– Comparison of Key Differences
Key Terms: Apical Meristem, Collenchyma, Cortex, Ground Meristem, Ground Tissue, Intercalary Meristem, Lateral Meristem, Meristematic Tissue, Mesophyll Tissue, Parenchyma, Pith, Sclerenchyma
What is Meristematic Tissue
Meristematic tissue refers to the cells that are capable of actively dividing. Therefore, the meristematic tissue can be found in the growing areas of the plant such as the tips of the root and shoot, leaf and the flower buds, and in the cambium layer of the stem. All the cells in the meristematic tissue are living cells with thin cell walls. These cells contain a few small vacuoles. The protoplasm is dense and contains a conspicuous nucleus. The shape of the cell can be either spherical, oval or polygonal. The cells do not have stored food. but, they are in an active state of metabolism.
Three types of meristematic tissue can be identified based on the origin and development. They are promeristem, primary meristem, and secondary meristem. Promeristem or the periodical meristem is found at the tip of the root and shoot. It gives rise to the primary meristem. The primary meristem can be found below the promeristem. It forms the permanent tissues. The secondary meristem originates from the primary permanent tissues and has the capacity to divide. The cork-cambium and the cambium in the root are the examples of the secondary meristem.
Based on the position, three types of meristem can be identified: apical meristem, intercalary meristem, and lateral meristem. The promeristem and the primary meristem, which can be found in the apices of the root and shoot are called apical meristem. The intercalary meristem is found between the permanent tissue, and the lateral meristem gives rise to the secondary permanent tissues.
Figure 1: The Coleus stem tip
A – Procambium, B – Ground meristem, C – Leaf gap, D – Trichome, E – Apical Meristem, F – Developing leaf primordia, G – Leaf primordium, H – Axillary bud, I – developing vascular tissue
Based on the function, the meristematic tissue can be divided into three categories: protoderm meristem, procambium meristem, and ground meristem. The protoderm meristem gives rise to the epidermal tissue. The procambium meristem is composed of narrow, elongated cells with tapering ends. It gives rise to vascular tissue. The ground meristem is composed of large cells with thick walls. It gives rise to the ground tissue in the pith, cortex, and the hypodermis. The different tissues in the Coleus stem tip are shown in figure 1.
What is Ground Tissue
Ground tissue refers to the cells found between the epidermal and vascular tissues. It consists of different types of cells, which are adapted to perform different types of functions. The ground tissue is derived from the ground meristem. The ground tissue in the stem can be divided into five zones. They are the cortex, endodermis, pericycle, pith, and the medullary rays. The cortex begins from the epidermis and ends up enveloping the stele. The secondary cortex is formed during the secondary growth of the plant. The cortex is composed of parenchyma cells. Collenchyma cells can be found in the superficial regions of herbaceous plants as well as in rapidly elongating bodies of floral and leafstalks. In some plants, a sclerenchyma cell layer can be found beneath the epidermis for structural support. The collenchyma and sclerenchyma cell layers found in the stem are commonly called the hypodermis. The innermost layer of the cortex is referred to as the endodermis. The cells in the endodermis are composed of Casparian strips. The pericycle surrounds the vascular tissues by one or several layers of cells. The main internal ground tissue in the stem is the pith. The cells in the pith serve as a storage tissue. The medullary rays can be found in between the vascular bundles. The tissue layers in the stem are shown in figure 2.
Figure 2: Tissues in a stem
1 – Pith, 2 – Protoxylem, 3 – Xylem, 4 – Phloem, 5 – Sclerenchyma, 6 – Cortex, 7 – Epidermis
The ground tissue in leaves are called the mesophyll tissue; this is mainly composed of photosynthesizing parenchyma cells. In monocots, the mesophyll tissue is composed of isodiametric cells with more intercellular spaces. In dicots, the mesophyll tissue is divided into two layers: the palisade and the spongy. The mesophyll tissue in the dicot leaf is shown in figure 3.
Figure 3: Mesophyll tissue in the leaf
Similarities Between Meristematic Tissue and Ground Tissue
- Meristematic tissue and ground tissue are two types of tissues found in plants.
- Both meristematic and ground tissue composed of parenchyma cells.
Difference Between Meristematic Tissue and Ground Tissue
Definition
Meristematic Tissue: Meristematic tissue is a tissue that is composed of cells that are capable of actively dividing and giving rise to differentiated cells in any type of tissue.
Ground Tissue: Ground tissue is a tissue of a plant other than the epidermis, periderm, and vascular tissues.
Capacity to Divide
Meristematic Tissue: Meristematic tissues are capable of actively dividing.
Ground Tissue: Ground tissues are incapable of dividing.
Composed of
Meristematic Tissue: Meristematic tissue is composed of parenchyma cells.
Ground Tissue: Ground tissue is composed of parenchyma, collenchyma, and sclerenchyma cells.
Types
Meristematic Tissue: The three types of meristematic tissue are apical meristem, intercalary meristem, and lateral meristem.
Ground Tissue: The three types of ground tissues are parenchyma, collenchyma, and sclerenchyma.
Presence
Meristematic Tissue: Meristematic tissues are found in the tips of shoots and roots, buds, and as a ring in the stem of the woody plants.
Ground Tissue: Ground tissue can be found in between the dermal and the vascular regions of the stem, roots, and leaves.
Function
Meristematic Tissue: Meristematic tissue is involved in the primary growth of the plant.
Ground Tissue: Ground tissue is involved in photosynthesis, storage, support, and regeneration.
Conclusion
Meristematic tissue and ground tissue are two types of tissues found in plants. The meristematic tissue mainly occurs in the apices of the root and shoot as well as in the leaf and flower buds. It consists of actively dividing cells. The ground meristem occurs between the epidermis and vascular tissue in the stem, root, and leaves. It is involved in the photosynthesis, storage, structural support, and regeneration. The cells in the ground tissue are incapable of dividing. The main difference between meristematic tissue and ground tissue is their location, function, and the ability to divide.
Reference:
1.“4 Types of Meristematic Tissues and their Functions.” Biology Discussion, 27 Aug. 2015, Available here. Accessed 26 Aug. 2017.
2.“Ground Tissue System of Plants (With Diagram).” Biology Discussion, 16 Oct. 2015, Available here. Accessed 26 Aug. 2017.
Image Courtesy:
1. “Coleus stemtip L” By Jon Houseman – Jon Houseman and Matthew Ford (CC BY-SA 4.0) via Commons Wikimedia
2. “Stem-histology-cross-section-tag” By SuperManu – own work based on Image: Labeledstemforposter copy.jpg by Ryan R. McKenzie (Public Domain) via Commons Wikimedia
3. “Leaf Tissue Structure” By Zephyris – Own work (CC BY-SA 3.0) via Commons Wikimedia
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