Wednesday, 27 May 2015

Topic : Tissues in Plants and Animals


Plants Tissues



Students hope this information collected in one place serves the purpose of learning the right way.

A group of cells performing a definite function are called Tissues. The cells that form a tissue are similar in structure , origin and function.

Study of tissues is known as Histology.


A process by which a common mass of cells assumes specific structure and function is called Differentiation.

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Plant Tissue Systems

The tissues of a plant are organized into three tissue systems: the dermal tissue system, the ground tissue system, and the vascular tissue system.
Tissue System
and Its Functions
Component TissuesLocation of Tissue Systems
Dermal Tissue System
• protection
• prevention of water loss
Epidermis
Periderm (in older stems and roots)
Ground Tissue System
• photosynthesis
• food storage
• regeneration
• support
• protection
Parenchyma tissue
Collenchyma tissue
Sclerenchyma tissue
Vascular Tissue System
• transport of water and minerals
• transport of food
Xylem tissue
Phloem tissue

Dermal Tissues

The dermal tissue system protects the soft tissues of plants and controls interactions with the plants' surroundings.
The epidermis is a dermal tissue that is usually a single layer of cells covering the younger parts of a plant. It secretes a waxy layer called the cuticle that inhibits water loss.

Some of the many types of cells in the epidermis are shown below.
Epidermis from onion

Most epidermal cells lack chloroplasts.
Epidermis from onion

Guard cells contain chloroplasts and regulate gas exchange between the inside of the leaf and the surrounding air.


Epidermal hairs lower water loss by decreasing the flow of air over the plant surface, which in turn, slows the loss of water from the plant.

Glandular hairs prevent herbivory by storing substances that are harmful to insects.

Root hairs increase water uptake by increasing the surface area of the cell.
In older stems and roots, the epidermis may be replaced by the periderm, which provides protection while permitting gas exchange.
Periderm

The outer layer of periderm, cork tissue, is composed of dead cells whose cell walls are impregnated with a waxy material, suberin.
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Vascular Tissues

Vascular tissue is composed of xylem and phloem, which function in the transport of water and dissolved substances.
Use the information in the table to help answer the questions below it.
Vascular TissueXylem TissuePhloem Tissue
Function• Conduct water and dissolved minerals
• Support
• Conduct food and other organic substances
Cell Types Unique to This TissueTracheids Vessel members
Companion
cells
Sieve-tube
elements
Additional Cell Types in This TissueParenchyma cells
Fibers
Parenchyma cells
Fibers
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 A summary of classification of Plant Tissues

Some important differences:
 

Difference between Simple and Complex tissues and Parenchyma Collenchyma and Sclerenchyma

Difference between Parenchyma Collenchyma and Sclerenchyma

Difference between Monocot stem and Dicot Stem

http://www.majordifferences.com/2013/03/difference-between-dicot-and-monocot.html#.VWk0bIs9LIU

 Difference between Diffusion and Osmosis

http://www.majordifferences.com/2013/11/difference-between-diffusion-and-osmosis.html#.VWk1o4s9LIU

 Animal Tissues

Following is a list of different types of Epithelial tissues ; location and their functions