Typically, these cells extremely long, extending from the root to the leaves, usually in parenchymatous tissue, but can pass through wood and phloem. In Ficus can reach the cuticle. Its walls are cellulose, hemicellulose and pectic substances with. They are often multinucleated, and maintain active metabolism while the surrounding tissues remain alive. The cytoplasm is a thin wall, which may contain grains of starch in various ways. They need to stay alive in order to grow and invade new tissues. The latex is a large central vacuole or multiple, is eccrine secretion. In some species are unbranched laticifers: Cannabis ( Moraceae ), Urtica ( Urticaceae ), Vinca ( Apocynaceae ). The apex of the cells reaches the vicinity of the meristem , and continually invade newly formed tissues by intrusive growth. Usually do not have intercellular communications. Once installed in the tissues, its growth is Symplast with other cells. In other species the laticiferous are branched, forming an extensive network: Asclepiadaceae , Ficus ( Moraceae ), Nerium ( Apocynaceae ), Euphorbia and Jathropha ( Euphorbiaceae ). In [[Asclepias syriaca]] and Nerium oleander was found that the laticifers contain pectinase, it is believed that this enzyme is released into the apex of the cell, to soften the middle lamella in tissues that are invaded. The initial cells of these laticifers can be seen already in the embryo: Cryptostegia , Nerium oleander , Euphorbia . Some plants form new initial new tissue, and a mature plant laticifers have more than a seedling.
laticíferas cell chains are connected together. In Allium each cell is connected with the neighbors by plasmodesmata , in other cases as in Musa are no real holes in the common wall, so that the mature laticiferous looks like a glass of xylem . When the end wall is completely occupied by the drilling can be confused with non-articulated laticifers. In many laticiferous articulated protoplasm degenerates into the final stage of development, or whether the discharge is holocrina. In some species, not anastomosing laticifers are articulated, as in Allium ( Alliaceae ), Musa ( Musaceae ), zapota Manilkara ( Sapotaceae ), Ipomoea ( Convolvulaceae ). Its development occurs by the continuous dedifferentiation of parenchyma cells in laticíferas cells at the ends. As new cells differentiate into laticíferas perforations are formed with older cells. First, the primary transverse wall thickens and swells, then dissolves the middle lamella, and finally provides a real piercing connecting the cytoplasm of two neighboring cells.
In other species the anastomosing laticifers are articulated, because the laticifers are fused together, forming a network tridimendional spanning the entire plant: Argemone , Papaver ( Papaveraceae ), Carica ( Caricaceae ), Cichorium , Lactuca , Taraxacum kok-saghyz ( Compositae ) , Hevea , Manihot ( Euphorbiaceae ). The fusion between neighboring laticifers differentiation occurs also in laticíferas parenchyma cells, forming a bridge. In Hevea brasiliensis , the tree from which rubber is extracted, the most important are in phloem and bark. The extraction is performed with a knife bleeding called "Jebong". Are made ??oblique at an angle of about 30 °, from left to right. The rubber is present in the cytoplasm, cell complexes called lutoides , 1-5 um in diameter and surrounded by a membrane. Constitutes up to 30% latex Hevea .
In botanical nomenclature (which also covers fungi ), the autónimos are names created automatically. Apply only to taxa resulting from the subdivision of a genus (Article 22 of the International Code of Botanical Nomenclature ) or a species (Art. 26 º), and only infrageneric taxa or infraspecific . Are considered published when it was published the first infrageneric or infraspecific taxon, although not explicitly referred to in that time. The specimen types are not designated as autónimos, since they are included in the type species (for infrageneric names), or the type of species (for infraspecific names). The specific epithet is always a repetition of the name of the genus or species, and cited no authority . The autónimos have scientific priority over other names published at the same time. Examples: Euphorbia sect. Euphorbia , Tricholoma (Fr.) Staude sect. Tricholoma , Festuca ovina subsp. sheep ; Tricholoma sulphureum ( Bull. : Fr) P. Kumm. var sulphureum .
Seolncr - About Author:
Prairie Florist Regina Saskatchewan flower shop offers same day delivery in Regina, Saskatchewan or on the date you specify with an order. For more info about flowers regina visit prairiefloristregina.ca
Published by Seolncr on January 31st 2012 | Business
Published by Seolncr on February 1st 2012 | Business
Published by Martin Peterson on April 22nd 2012 | Business
Published by Seolncr on February 3rd 2012 | Business
Published by Seolncr on January 26th 2012 | Business
Published by Seolncr on January 30th 2012 | Business
Published by Roney on February 6th 2012 | Business
Published by Seolncr on February 2nd 2012 | Business
Published by Seolncr on February 15th 2012 | Business
Published by Seolncr on February 4th 2012 | Business
Published by Seolncr on May 4th 2012 | Business
Published by Seolncr on February 4th 2012 | Business