Recommended
More Related Content
What's hot
What's hot (20)
Similar to Cell Ingrowths: Adcrustation & Incrustation, Transport cells
Similar to Cell Ingrowths: Adcrustation & Incrustation, Transport cells (20)
More from Nistarini College, Purulia (W.B) India
More from Nistarini College, Purulia (W.B) India (20)
Recently uploaded
Recently uploaded (20)
Cell Ingrowths: Adcrustation & Incrustation, Transport cells
- 1. Cell Wall ingrowths: Adcrustation & Incrustation By N.Sannigrahi, Associate Professor, Department of Botany, Nistarini College, Purulia, 723101(W.B) India
- 2. Adcrustation is the process of addition of any substance particularly the secondary materials from inside the whole substance .It means that nothing is added on the surface of the body to make the substances thick or big , rather the growth comes from the whole body. The growth of the fruits is an ideal example. Incrustation , on the other hand, is the process by which the substances grow with the addition of new layers on the surface of the body. The cell wall of the plants grow by the process of incrustation.
- 3. When certain organic molecules penetrate the primary wall and undergoes polymer formation, the cell wall undergoes incrustation. Lignin is the most important incrusting substances and it is insoluble constituent of the cell wall, aromatic and of high molecular weight. It is synthesized by the oxidative polymerization of monolignols like coumaryl, coniferyl and sinapyl alcohols-the products of phenylpropane pathway. During the incrustation of the cell wall with lignin, the more hydrophilic matrix sinks and is compressed by the displacement of water. It occurs predominantly in the region of the middle lamellae. Incrustation with lignin decreases the water permeability of the wall and the lignin deposits add mechanical strength.
- 4. It is the process in which the outer walls of the epidermis of leaves and other aerial regions, the walls of cork cells, certain walls of inner sheaths in roots and shoots are covered or impregnated by cutins and suberins. Cutin & wax occur on plant surfaces and the wax contains fatty acids of 16-18 carbons is responsible for the hydrophobic characters of cuticle and to hinder evaporation particularly in the xerophytes. Suberin, 20-30 carbon atoms of long fatty acids and polyphenols , cork cells walls are generally tightly anchored to the plasma membrane assuring total water insulation. Suberization also alters permeability of the cell walls .Complete suberization of the wall barks and corks prevents the contact between the cells and the environment that sometimes leads to eventual cell death.
- 5. The formation of wall ingrowths increases plasma membrane surface areas of transfer cells involved in membrane transport of nutrients in plants. Construction of these ingrowths provides intriguing and diverse examples of localized wall deposition. Flange wall ingrowths resemble secondary wall thickenings of tracheary elements in morphology and probable mechanisms of deposition. By contrast, reticulate wall ingrowths, deposited as discrete papillate projections, branch and fuse to create a fenestrated wall labyrinth representing a novel form of localized wall deposition. Papillate wall ingrowths are initiated as patches of disorganized cellulosic material and are compositionally similar to primary walls, except for a surrounding layer of callose and enhanced levels of arabinogalactan proteins at the ingrowth /membrane interface..
- 6. How this unusual form of localized wall deposition is constructed is unknown but may involve constraining cellulose-synthesizing rosette complexes at their growing tips. Transfer cells are frequently located at sites of intensive membrane transport of nutrients (Gunning and Pate 1969 , Offler et al. 2003 ). The unique feature of these anatomically specialized cells is the presence of intricately invaginated wall ingrowths, the contours of which are followed by plasma membrane enriched in transporter proteins (Harrington et al. 1997 ). The increased surface area of plasma membrane, and concentration of transporter proteins, facilitates elevated rates of nutrient transport across the symplasmic–apoplasmic interface (Patrick and Offler 1995 , Patrick 1997 ).
- 7. The transfer cells first coined by Brain E.S. Gunning & John Pate (1969) are characterized by i. enlarged lobed nucleus, numerous ER Cisternae, numerous mitochondria and ribosome, Plasmodesmata connect transfer cells to other transfer cells and to parenchyma cells, The wall ingrowths are formed just as intensive transport begins, become first developed on the faces of the cell presumed to be most active in solute transport It is apparently restricted to situations where adverse surface to volume relationship exist between donor and receptor compartments of the transport pathway The cell wall ingrowths of these cells provide intriguing amnual diverse examples of localized wall depositions.
- 10. The transfer cells functions relate to any of the four categories of transmembrane flux as follows: Absorption of solute from the external environment like epidermis of the submerged leaves, Secretion of solutes to the external medium like nectaries and other glands, Absorption of solutes from the internal, extra cytoplasmic compartment like vascular parenchyma, haustorial type connections, embryo sac, Secretion of solutes into an extra cytoplasmic compartment like tapetum of anther, pericycle of root nodule etc. Besides, the transfer cells form an anti-pathogenic barrier at the symplastic discontinuties.As the transfer cells help in nutrient transport, they are important in plant development and crop productivity.