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Ergastic Substances 1. Ergastic Substances or Cell Inclusions Cell Inclusions are non-living substances present in the cells. They are also called ergastic substances or ergastic bodies. They may be present in soluble or insoluble state and can be organic or inorganic in nature.
These are present in components or sub-components of cell. They are raw materials or products of metabolism. THEY may be exported or expelled from the cell. The grains are found in chloroplasts and amyloplasts. As such they are insoluble. The grains may occur singly when they are called simple.
They are called compound starch grains when two or more of them occur in amyloplasts. Starch is deposited around it in the form of layers. Depending upon the position of hilum,a starch grain may be concentric or eccentric. Tanniferous bodies are widely distributed in different parts of the plant body and they are particularly abundant in leaves,vascular tissues,periderm,unripe fruits,seed coat.
They are small granular or rounded particles,yellow,red or brown in color. These phenolic compounds are commercially useful in tanning industry.
Other soid and semi-solid substances,such as oils,fats and waxes also occur frequently. Oils and fats are common reserve materials of seeds,while waxes occur usually as protective covering on the epidermis.
Calcium oxalate crystals are most common in plants. Their shape varies considerably and may be elongated,needle-like, rectangular,rhomboidal,sphaeroidal or prismatic. Crystals of inorganic compounds, such as silica and gypsum although uncommon are also present in some plants. Cystoliths, which are internal outgrowth of cell wall occur in many plants. Sclerenchyma cells Mature sclerenchyma cells are dead and have secondary cell walls thickened with cellulose and usually impregnated with lignin.
In contrast to collenchyma, which is pliable able to fold , sclerenchyma is elastic. Unlike the collenchyma, mature sclerenchyma is composed of dead cells. It is the hard, thick walls that make sclerenchyma cells important strengthening and supporting elements in plant parts that have ceased elongation Fibres: The cells are needle-shaped with pointed tips, thick walls and rather small lumen. Secondary cell walls, impregnated with, are formed. Simple pits are also present.
Fibres are abundant in the vascular tissue of angiosperms, i. Typical examples are the fibres of many grasses, agaves. Their cell walls contain, besides cellulose, a high proportion of lignin. Starting at the centre of the fibre are the thickening layers of the secondary wall deposited one after the other. Growth at both tips of the cell leads to simultaneous elongation.
During development ,the layers of secondary material seem like tubes, of which the outer one is always longer and older than the next. After completion of growth the missing parts are supplemented, so that the wall is evenly thickened up to the tips of the fibres.
Some of the well-nown sources and usages of bst fibres are hemp Cannabis sativa ,jute Corchorus capsularis ,flaax Linum usitatissimum ,textiles e. The fibres of monocotyledons-usually called leaf fibres because they are obtained from leaves-are classified as hard fibres. Examples of sources and uses of leaf fibres are Manila hemp Musa textilis ,Pineapple fibre Ananas comosus and Sisal Agave sisalana.
Leaf fibres of monocotyledons together with the xylem serve as raw material for making paper. The cell walls are thick, hard and lignified which makes the lumen very small. Simple pits canals are found in the thickened cell walls and link adjacent cells. Sclereids are commonly found in fruit and seeds. These have a shape of a star. They can be grouped into bundles, can form complete tubes located at the periphery or can occur as single cells or small groups of cells within parenchymatissues.
But compared with most fibres, sclereids are relatively short Macrosclereids Osteosclereids: They are bone or barrel shaped and dilated at ends. They occur in the leaves and seed coat of many cot many monocotyledons.
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Ergastic Crystal Studies for Raw Drug Analysis
Ergastic substances are non- protoplasm materials that one can find in cells. These are usually products of metabolism. Ergastic substances include crystals , oil drops, gums , tannins , resins and other compounds. Some of these substances help the organism function, keep up cell structure, or are just stored food material such as oil or fat. During the life of a cell, they can appear and disappear. Ergastic substances may appear in the protoplasm , in vacuoles , or in the cell wall. Ergastic substances are usually absent in tissue with dividing cells, such as meristem tissue in plants.
Ergastic substances are non- protoplasmic materials found in cells. The living protoplasm of a cell is sometimes called the bioplasm and distinct from the ergastic substances of the cell. The latter are usually organic or inorganic substances that are products of metabolism, and include crystals, oil drops, gums, tannins , resins and other compounds that can aid the organism in defense, maintenance of cellular structure, or just substance storage. Ergastic substances may appear in the protoplasm , in vacuoles , or in the cell wall. Reserve carbohydrate of plants are the derivatives of the end products of photosynthesis. Cellulose and starch are the main ergastic substances of plant cells.