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Post a LessonAnswered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
Meristems are regions of plant tissue composed of actively dividing cells. They are responsible for the growth and development of plants. There are three main types of meristems in plants, each located in specific regions and serving distinct functions:
Apical Meristem:
Lateral (or Cambial) Meristem:
Intercalary Meristem:
These different types of meristems work together to ensure the growth, development, and adaptation of plants to their environment. They play crucial roles in primary and secondary growth, tissue differentiation, and the formation of new organs and structures throughout the life cycle of plants.
Answered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
Yes, I agree with the statement that cork cambium forms tissues that form the cork. Cork cambium, also known as phellogen, is a type of lateral meristem found in the bark of woody stems and roots of certain plants. It is responsible for the production of cork cells (phellem) that constitute the outer protective layer of the stem or root, known as the cork or periderm.
Cork cambium is a layer of meristematic tissue that arises from the activity of the vascular cambium or the phloem parenchyma cells. As the cork cambium undergoes cell division, it produces new cells towards both the outer and inner sides. The cells produced towards the outer side differentiate into cork cells, while those produced towards the inner side differentiate into phelloderm cells, which are part of the secondary cortex.
The cork cells produced by the cork cambium are dead at maturity and have several specialized features that make them suitable for their protective function. Cork cells are filled with suberin, a waxy substance that makes them impermeable to water and gases, providing a barrier against desiccation, pathogens, and mechanical damage. Additionally, cork cells have thick cell walls and are arranged in layers, forming a durable and protective outer covering for the plant.
Overall, cork cambium plays a crucial role in the formation of cork tissues, which serve as a protective barrier for the underlying tissues of woody stems and roots. Without the activity of cork cambium, plants would be more susceptible to damage from environmental stresses, pathogens, and physical injuries. Therefore, it is accurate to say that cork cambium forms tissues that form the cork.
Answered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
Secondary growth in the stems of woody angiosperms occurs due to the activity of two lateral meristems: the vascular cambium and the cork cambium (phellogen). These meristems add layers of secondary tissues, resulting in an increase in girth or diameter of the stem. Here's an explanation of the process of secondary growth along with schematic diagrams illustrating the key steps:
Process of Secondary Growth:
Vascular Cambium Activity:
Cork Cambium Activity:
Schematic Diagrams:
Annual Rings Formation
_______________________________________
| |
| Secondary Phloem (Bark) |
|______________________________________|
| |
| Secondary Xylem (Wood) |
|______________________________________|
| Vascular Cambium (Meristem) |
|______________________________________|
| Primary Phloem (Old Bark) |
|______________________________________|
| Primary Xylem (Old Wood) |
|______________________________________|
| Pith (Central Region) |
|______________________________________|
Cork Cambium Activity
_______________________________________
| |
| Cork (Phellem) |
|______________________________________|
| Cork Cambium |
|______________________________________|
| Phelloderm |
|______________________________________|
| Secondary Phloem |
|______________________________________|
| Secondary Xylem |
|______________________________________|
| Primary Phloem (Old Bark) |
|______________________________________|
| Primary Xylem (Old Wood) |
|______________________________________|
| Pith (Central Region) |
|______________________________________|
Significance of Secondary Growth:
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Answered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
Below are simplified illustrations highlighting the anatomical differences between a monocot root and a dicot root:
___________________
/ \
| Epidermis |
|___________________|
| |
| Cortex Region |
|___________________|
| |
| Endodermis |
|___________________|
| |
| Pericycle |
|___________________|
| |
| Vascular Bundles |
|___________________|
| |
| Pith (Parenchyma)|
|___________________|
Dicot Root Anatomy:
___________________
/ \
| Epidermis |
|___________________|
| |
| Cortex Region |
|___________________|
| |
| Endodermis |
|___________________|
| |
| Pericycle |
|___________________|
| |
| Vascular Bundle |
|___________________|
| |
| Pith (Parenchyma)|
|___________________|
Anatomical Differences:
Vascular Bundle Arrangement:
Pith Presence:
Cortex Thickness:
Endodermis and Pericycle:
Epidermis:
Answered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
To ascertain whether the transverse section of the young stem is from a monocot or a dicot plant, I would observe several anatomical features under the microscope and compare them to known characteristics of monocot and dicot stems. Here's how I would differentiate between the two:
Monocot Stem:
Vascular Bundles:
Xylem and Phloem Arrangement:
Ground Tissue (Cortex):
Dicot Stem:
Vascular Bundles:
Xylem and Phloem Arrangement:
Pith Presence:
Observations:
By observing these key anatomical features under the microscope, I can accurately determine whether the stem section is from a monocot or a dicot plant.
Answered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
Based on the provided anatomical features, the transverse section of the plant material can be identified as that of a monocot stem. Here's why:
Conjoint and Scattered Vascular Bundles:
Surrounded by Sclerenchymatous Bundle Sheath:
Absence of Phloem Parenchyma:
Based on these characteristics, the presence of conjoint and scattered vascular bundles surrounded by a sclerenchymatous bundle sheath and the absence of phloem parenchyma, the transverse section of the plant material can be confidently identified as that of a monocot stem.
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Answered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
Xylem and phloem are called complex tissues because they are composed of more than one type of cell, each performing specialized functions. In both xylem and phloem, various cell types work together to facilitate the transport of water, nutrients, and other substances throughout the plant.
In xylem tissue, the main cell types include:
In phloem tissue, the main cell types include:
The complex organization and arrangement of these different cell types within xylem and phloem allow for efficient and directional transport of fluids and nutrients, making them essential for the growth and survival of plants.
read lessAnswered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
a) Prostomium and Peristomium:
Prostomium:
Peristomium:
Key Difference:
b) Septal Nephridium and Pharyngeal Nephridium:
Septal Nephridium:
Pharyngeal Nephridium:
Key Difference:
Answered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
The circulatory system of an earthworm is relatively simple compared to more complex vertebrates. It consists of a closed system of blood vessels that transport nutrients, gases, and metabolic wastes throughout the body. Here's a brief overview of the circulatory system of an earthworm:
Dorsal Blood Vessel:
Ventral Blood Vessel:
Segmental Vessels:
Aortic Arches (Hearts):
Hemolymph:
Overall, the circulatory system of an earthworm efficiently distributes essential substances and facilitates gas exchange between tissues, ensuring proper functioning and survival of the organism.
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Answered on 09 Apr Learn Chapter 6- Anatomy of Flowering Plants
Sadika
Epithelial tissues are one of the four basic types of animal tissues, and they cover the body surface, line body cavities, and form glands. There are several types of epithelial tissues, each specialized for different functions and found in various parts of the body. Here, I'll describe four types of epithelial tissues along with labelled diagrams:
Description: Simple squamous epithelium consists of a single layer of flat, scale-like cells. These cells are thin and flattened, allowing for rapid diffusion and filtration across the epithelium.
Location: Found in areas where rapid diffusion or filtration occurs, such as the alveoli of the lungs, blood vessels (endothelium), and the lining of the body cavities (mesothelium).
Function: Facilitates diffusion of gases (oxygen and carbon dioxide) in the lungs, filtration of blood in the kidneys, and lubrication of body cavities.
Labelled Diagram:
Basement Membrane Simple Squamous Epithelium __________________________________
Description: Simple cuboidal epithelium consists of a single layer of cube-shaped cells. These cells have centrally located nuclei and may contain microvilli or cilia on their apical surface.
Location: Found in kidney tubules, ducts of glands (e.g., thyroid gland), and the surface of the ovaries.
Function: Involved in absorption, secretion, and excretion. In the kidneys, it facilitates reabsorption and secretion of substances, while in glands, it aids in the secretion of hormones and enzymes.
Labelled Diagram:
Basement Membrane Simple Cuboidal Epithelium __________________________________
Description: Simple columnar epithelium consists of a single layer of tall, column-shaped cells. These cells often have elongated nuclei located near the basal surface and may contain microvilli or cilia on their apical surface.
Location: Found in the lining of the gastrointestinal tract (stomach, small intestine, large intestine), uterine tubes, and portions of the respiratory tract.
Function: Involved in absorption, secretion, and protection. It aids in the absorption of nutrients and secretion of mucus and enzymes in the digestive tract.
Labelled Diagram:
Basement Membrane Simple Columnar Epithelium __________________________________
Description: Stratified squamous epithelium consists of multiple layers of flattened cells. The basal layers are cuboidal or columnar, while the superficial layers are squamous.
Location: Found in the epidermis of the skin, lining of the oralcavity, esophagus, andvagina.
Function: Provides protection against mechanical abrasion, pathogens, and dehydration. It forms a tough, impermeable barrier in areas subjected to wear and tear.
Labelled Diagram:
Basement Membrane Stratified Squamous Epithelium __________________________________
These diagrams illustrate the structure and organization of each type of epithelial tissue, highlighting their distinct characteristics and functions in the body.
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