Please inform me where I can find internal structure of roots and leaves
Answers
Answered by
0
INTERNAL STRUCTURE OF ROOT Internally, a root has the following parts: epidermis, cortex, vascular tissue (xylem & phloem) and root cap.
TRANSVERSE SECTION SHOWING INTERNAL STRUCTURES OF DICOTYLEDONOUS ROOT
These structures are put into four main zones/regions including .. the root cap, meristematic region, region of elongated and region of maturation (or differentiation).
The Root Cap (Region of Cell Division)
One of its functions is to protect the delicate tissues of the root from mechanical damage as the young root grows through the soil. The region is composed of a loosely arranged parenchyma cells located at the tip of the roots. The root tip pushes through abrasive soilparticles. The parenchyma cells, which are re laced from the inside, constantly; slough off, forming a slimy lubricant that facilitates movement through the soil.
MERISTEMATIC REGION
Cells in this region produce the root cap. It is composed of apical meristem i.e. a region of active cell division that occurs relatively close to the tips of roots and shoot of plants. This adds new cells to the root cap and also provides new cells that increase the length of the root.
REGION OF ELONGATION
Cells produce in the meristematic region absorb water and develop vacuoles. As water fills the vacuole the cells elongates. The increase in the length of these cells pushes the meristematic region and the root cap further into the soil.
REGION OF MATURATION
In this region most of the cells mature into the various distinctive cells type of the primary tissues. This region is often referred to as the region of differentiation. Primary tissue formed includes the epidermis, vascular tissue (xylem & phloem) and root hairs. The root hairs often grow from an area of the epidermis called the piliferous layer. These root hairs form part of the epidermis cells and greatly increase the absorptive surface of the root as they absorb water and mineral ions from the soil.
INTERNAL STRUCTURE OF A LEAF
A typical leaf consists of three main regions:
These are: epidermis mesophyll and vascular bundle.
EPIDERMIS
This is a single layer of cells occurring on both surface of the lamina/leaf blade. It consists of cells which have no chloroplast. The epidermis on the lower surface of the lamina can be distinguished from that of the upper surface by the presence of the stomata (minute pore). Two beans-shaped cells called guard cells enclosed each stoma. These cells contain chloroplasts with which they regulate the size of the stomata by varying their turgidity and thus control gas exchange between internal environment of the leave and the atmosphere.
CUTICLE
The exposed surface of the cells of the upper and lower epidermis is covered with cuticle. Functionally, the cuticle prevents loss of water from the leaf thorough the epidermal cells. It also protects the internal tissues and cells from mechanical damage by bacteria and fungi.
STOMATA
These are tiny holes or openings in the epidermis.
They are found between epidermal cells.
They vary in size in different plants. Stomata are more numerous in the lower epidermis than in the upper epidermis. Functionally. the stomata allow entry and exits of carbon dioxide and oxygen which are used for photosynthesis and respiration respectively.
PALISADE MESOPHYLL
Located immediately below the upper epidermis. The cells contain many chloroplasts. Because it contains many chloroplasts, its main function is to carry out photosynthesis.
MESOPHYLL
This consists of the tissue between the upper and lower epidermis. its cells are thin-walled and contain chloroplasts. Unlike the monocot, the mesophyll of the dicot is made up of two types of cells. The upper mesophyll cell has many chloroplasts and spaces between them and this constitute the palisade tissue. The latter is made up of irregular shaped; loosely packed cells with fewer chloroplasts and air spaces between them make up the spongy tissue, within these two layers, is the vascular bundle.
THE VASCULAR BUNDLE
Veins of various sizes are scattered throughout the mesophyll. They consist mainly of xylem and phloem tissues, and provide mechanical strength, i.e. provide its skeleton. The carbohydrates produce in the mesophyll cells are transported in solution throughout the plants by the phloem whilst the xylem conducts Water and mineral ions into the leaf.
TRANSVERSE SECTION SHOWING INTERNAL STRUCTURES OF DICOTYLEDONOUS ROOT
These structures are put into four main zones/regions including .. the root cap, meristematic region, region of elongated and region of maturation (or differentiation).
The Root Cap (Region of Cell Division)
One of its functions is to protect the delicate tissues of the root from mechanical damage as the young root grows through the soil. The region is composed of a loosely arranged parenchyma cells located at the tip of the roots. The root tip pushes through abrasive soilparticles. The parenchyma cells, which are re laced from the inside, constantly; slough off, forming a slimy lubricant that facilitates movement through the soil.
MERISTEMATIC REGION
Cells in this region produce the root cap. It is composed of apical meristem i.e. a region of active cell division that occurs relatively close to the tips of roots and shoot of plants. This adds new cells to the root cap and also provides new cells that increase the length of the root.
REGION OF ELONGATION
Cells produce in the meristematic region absorb water and develop vacuoles. As water fills the vacuole the cells elongates. The increase in the length of these cells pushes the meristematic region and the root cap further into the soil.
REGION OF MATURATION
In this region most of the cells mature into the various distinctive cells type of the primary tissues. This region is often referred to as the region of differentiation. Primary tissue formed includes the epidermis, vascular tissue (xylem & phloem) and root hairs. The root hairs often grow from an area of the epidermis called the piliferous layer. These root hairs form part of the epidermis cells and greatly increase the absorptive surface of the root as they absorb water and mineral ions from the soil.
INTERNAL STRUCTURE OF A LEAF
A typical leaf consists of three main regions:
These are: epidermis mesophyll and vascular bundle.
EPIDERMIS
This is a single layer of cells occurring on both surface of the lamina/leaf blade. It consists of cells which have no chloroplast. The epidermis on the lower surface of the lamina can be distinguished from that of the upper surface by the presence of the stomata (minute pore). Two beans-shaped cells called guard cells enclosed each stoma. These cells contain chloroplasts with which they regulate the size of the stomata by varying their turgidity and thus control gas exchange between internal environment of the leave and the atmosphere.
CUTICLE
The exposed surface of the cells of the upper and lower epidermis is covered with cuticle. Functionally, the cuticle prevents loss of water from the leaf thorough the epidermal cells. It also protects the internal tissues and cells from mechanical damage by bacteria and fungi.
STOMATA
These are tiny holes or openings in the epidermis.
They are found between epidermal cells.
They vary in size in different plants. Stomata are more numerous in the lower epidermis than in the upper epidermis. Functionally. the stomata allow entry and exits of carbon dioxide and oxygen which are used for photosynthesis and respiration respectively.
PALISADE MESOPHYLL
Located immediately below the upper epidermis. The cells contain many chloroplasts. Because it contains many chloroplasts, its main function is to carry out photosynthesis.
MESOPHYLL
This consists of the tissue between the upper and lower epidermis. its cells are thin-walled and contain chloroplasts. Unlike the monocot, the mesophyll of the dicot is made up of two types of cells. The upper mesophyll cell has many chloroplasts and spaces between them and this constitute the palisade tissue. The latter is made up of irregular shaped; loosely packed cells with fewer chloroplasts and air spaces between them make up the spongy tissue, within these two layers, is the vascular bundle.
THE VASCULAR BUNDLE
Veins of various sizes are scattered throughout the mesophyll. They consist mainly of xylem and phloem tissues, and provide mechanical strength, i.e. provide its skeleton. The carbohydrates produce in the mesophyll cells are transported in solution throughout the plants by the phloem whilst the xylem conducts Water and mineral ions into the leaf.
Similar questions