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Organisation of cells plant tissues (view source)
Revision as of 13:58, 31 July 2014
, 13:58, 31 July 2014→Notes for teachers
Parenchyma, in plants, tissue typically composed of living cells that are thin-walled, unspecialized in structure, and therefore adaptable, with differentiation, to various functions. Parenchyma may be compact or have extensive spaces between the cells. It is often called ground, or fundamental, tissue and makes up the mesophyll (internal layers) of leaves and the cortex (outer layers) and pith (innermost layers) of stems and roots; it also forms the soft tissues of fruits. Cells of this type are also contained in xylem and phloem as transfer cells and, with both xylem and phloem as bundle sheaths, the cells that surround the vascular strands.<br>
Parenchyma, in plants, tissue typically composed of living cells that are thin-walled, unspecialized in structure, and therefore adaptable, with differentiation, to various functions. Parenchyma may be compact or have extensive spaces between the cells. It is often called ground, or fundamental, tissue and makes up the mesophyll (internal layers) of leaves and the cortex (outer layers) and pith (innermost layers) of stems and roots; it also forms the soft tissues of fruits. Cells of this type are also contained in xylem and phloem as transfer cells and, with both xylem and phloem as bundle sheaths, the cells that surround the vascular strands.<br>
http://www.mhhe.com/biosci/pae/botany/histology/images/parench.jpg
http://www.mhhe.com/biosci/pae/botany/histology/images/parench.jpg<br>
Parenchyma tissue
Parenchyma tissue<br>
Parenchyma tissue is composed of loosely packed thin wall cells so that large spaces between cells(intercellular spaces) are found in this tissue. This tissue provides support to plants and also stores food. In some situations, it contains chlorophyll and performs photosynthesis, and then it is called
chlorenchyma. In aquatic plants like pistia and lotus, large air cavities are present in parenchyma to give buoyancy to the plants to help them float.Such a parenchyma type is called aerenchyma. The parenchyma of stems and roots also stores nutrients and water.<br>
COLLENCHYMA TISSUE:<br>
The flexibility in plants is due to another permanent tissue, collenchyma. It allows easy bending in various parts of a plant (leaf,stem,petiole) without breaking. It also provides mechanical support to plants. We can find this tissue in leaf stalks below the epidermis.The cells of this tissue are living, elongated and irregularly thickened at the corners. There is very little intercellular space.The cell wall is made up of cellulose and pectin.<br>
===Activities===
===Activities===
