Differentiation of cells and diversity of plant tissues
Organization of living organisms
The human body is composed of many systems integrate together forming the body of the living organism , such as the circulatory , nervous , digestive , respiratory , excretory and reproductive systems .
We will take the human as an example of multicellular living organisms to identify his body building, The system is composed of a group of organs work together, such as the circulatory system which consists of the heart , blood and blood vessels .
The organ is composed of a group of tissues organized together to perform certain functions, such as the heart which consists of a cardiac muscular tissue, nervous tissue and connective tissue that collaborate together to pump the blood from the heart to all body parts.
The tissue is composed of a group of cells specialized in their work and if these cells forming the tissue are symmetrical with each other in the structure , shape and function , the tissue is called simple tissue and if there are more than one type of cells , the tissue is called compound tissue .
Simple tissue consists of only one type of cells that similar in structure , shape and function , Compound tissue consists of more than one type of cells .
Tissues are varied depending on the difference and diversity of living organisms , vital activities and functions they perform .
Human body consists of many systems that consist of many organs , The organs consist of many tissues , The tissues consist of many cells .
Plant tissues can be differentiated into simple and compound tissues , Simple tissues such as ( Collenchyma tissue , Parenchyma tissue and Sclerenchyma tissue ) , Compound tissues such as Conductive tissues ( Xylem tissue and phloem tissue ) .
Functions : Do photosynthesis , Store nutrients such as starch and responsible for aeration, It is a living tissue , its cells are characterized by the following :
Oval or rounded shaped , Their walls are thin and elastic , There are spaces ( intercellular spaces ) between them for aeration , It contains chloroplasts , chromoplasts or leucoplasts , It contains one big vacuole or more filled with water and mineral salts .
It is a living tissue , its cells are characterized by the following : Somewhat rectangular shaped , Their walls irregularly thickened with cellulose .
Function : Supporting the plant by acquiring it a suitable elasticity .
It is a non-living tissue , its cells are characterized by : their walls are thickened by lignin substance in addition to cellulose and solid tissue .
Functions : Strengthening and supporting the plant by acquiring it the hardness and elasticity .
Structure : It consists of vessels , tracheids and parenchyma cells , The vessels are tubes , each of them is made up of a vertical row of cells , where : protoplasm and transverse walls were disappeared , Lignin substance was deposited on inner surface of their walls at the inside .
So, these cells are converted into long wide vessels transporting the water and salts, their length ranges from few centimetres to several metres as in high trees.
The tracheids : Each of them is composed of one cell , where protoplasm disappeared from it , Their walls get lignified .
Functions : Supporting the plant, Transporting the water and salts from the root to the stem and leaves.
Structure : It consists of sieve tubes and companion cells .
The sieve tubes originate from compact cells , vertically above each other , where : Their nuclei disappeared , Their separating walls became perforated ( So , they are called sieve plates ) through which cytoplasm passes in the form of cytoplasmic strands .
The companion cells are living cells located adjacent to the sieve tubes to provide them with the energy they required to perform their function .
Function : Transporting the nutrients resulted in photosynthesis from the leaves to the other plant parts.