Aim: To study and identify various plant tissues
Procedure: Ask your teacher to show you permanent slides of meristematic, parenchyma,
collenchyma, sclerenchyma, xylem and phloem tissues.
Observe the slides under a
microscope and identify them.
Draw neat and labelled diagrams of the tissues as you see them.
Write two characteristics of each kind of tissue.
Answers
Answer:
Hope It will help
Explanation:
In biology, tissue is a cellular organizational level between cells and a complete organ. A tissue is an ensemble of similar cells and their extracellular matrix from the same origin that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues.
Plants
In plant anatomy, tissues are categorized broadly into three tissue systems: the epidermis, the ground tissue, and the vascular tissue.
Epidermis – Cells forming the outer surface of the leaves and of the young plant body.
Vascular tissue – The primary components of vascular tissue are the xylem and phloem. These transport fluids and nutrients internally.
Ground tissue – Ground tissue is less differentiated than other tissues. Ground tissue manufactures nutrients by photosynthesis and stores reserve nutrients.
Plant tissues can also be divided differently into two types:
1. Meristematic tissues
2. Permanent tissues.
Meristematic tissues
Meristematic tissue consists of actively dividing cells and leads to increase in length and thickness of the plant. The primary growth of a plant occurs only in certain, specific regions, such as in the tips of stems or roots. It is in these regions that meristematic tissues are present. Cells in these tissues are roughly spherical or polyhedral, to rectangular in shape, and have thin cell walls. New cells produced by meristem are initially those of meristem itself, but as the new cells grow and mature, their characteristics slowly change and they become differentiated as components of the region of occurrence of meristematic tissues, being classified as:
Apical meristem – It is present at the growing tips of stems and roots and increases the length of the stem and root. They form growing parts at the apices of roots and stems and are responsible for the increase in length, also called primary growth. This meristem is responsible for the linear growth of an organ.
Lateral meristem – This meristem consists of cells which mainly divide in one plane and cause the organ to increase in diameter and girth. Lateral meristem usually occurs beneath the bark of the tree in the form of Cork Cambium and in vascular bundles of dicots in the form of vascular cambium. The activity of this cambium results in the formation of secondary growth.
Intercalary meristem – This meristem is located in between permanent tissues. It is usually present at the base of the node, internode and on leaf base. They are responsible for growth in length of the plant and increasing the size of the internode. They result in branch formation and growth.
The cells of meristematic tissues are similar in structure and have thin and elastic primary cell wall made up of cellulose. They are compactly arranged without inter-cellular spaces between them. Each cell contains a dense cytoplasm and a prominent nucleus. The dense protoplasm of meristematic cells contains very few vacuoles. Normally the meristematic cells are oval, polygonal or rectangular in shape.
Meristematic tissue cells have a large nucleus with small or no vacuoles as they have no need to store anything, opposed to their function of multiplying and increasing the girth and length of the plant, and no intercellular spaces.
Permanent tissues
Permanent tissues may be defined as a group of living or dead cells formed by meristematic tissue and have lost their ability to divide and have permanently placed at fixed positions in the plant body. Meristematic tissues that take up a specific role lose the ability to divide. This process of taking up a permanent shape, size and a function is called cellular differentiation. Cells of meristematic tissue differentiate to form different types of permanent tissues. There are 3 types of permanent tissues:
simple permanent tissues
complex permanent tissues
special or secretory tissues (glandular).
Simple Permanent tissues
A group of cells which are similar in origin; similar in structure and similar in function are called simple permanent tissue.
Ik it is big. But it is my answer. Hope it will help