Tissue collenchyma

The most metabolic activity of plants is carried out in the tissue called parenchyma, which generally makes up the bulk of the volume of all soft edible plant structures. The epidermis, which sometimes is replaced by a layer of corky tissue, is structurally modified to protect the surface of the organ. The highly specialized tissues collenchyma and sclerenchyma provide mechanical support for the plant. Water, minerals, and products of metabolism are transported from one part to another of the plant through the vascular tissues, xylem and phloem, which are the most characteristic anatomical features of plants on the cross section. 

Collenchyma Collenchyma cells Flexible/extensible support for growing primary tissues... 

There are several kinds of plant tissues. Undifferentiated, embryonic cells found in rapidly growing regions of shoots and roots form the meristematic tissue. By differentiation, the latter yields the simple tissues, the parenchyma, collenchyma, and scleren-chyma. Parenchyma cells are among the most abundant and least specialized in plants. They give rise through further differentiation to the cambium layer, the growing layer of roots and stems. They also... 

From 50 g fresh weight of parenchyma tissue which does not contain starch, the expected recovery is -400 mg of cell walls, whereas, from 50 g fresh weight of parenchyma tissue containing a large amount of starch, the yield is -300 to 350 mg. The yield of cell walls from collenchyma tissue would be much higher due to the thicker cell walls, and yields of -6 g have been obtained from 50 g fresh weight. 

Esau, K. (1936). Ontogeny and structure of collenchyma and of vascular tissues in celery petioles.11,431-467. 

Periblem originates cortex tissue, chlorophylloid cells (chlor-enchyma) colloid cells (collenchyma), strengthening cells (scleren-chyma), crystal cells (raphiderchyma) latex cells (lacterchyma), endodermis and cork cambium. 

Fig. 71.—Portion of cross-section of four-year-old stem of Aristolochia sipho, as shown by the rings of growth in the wood. The letters are the same as in Pig. 68 but new tissues have been added by the activity of the cambium and a cork cambium has arisen from the outermost collenchyma cells and given rise to cork. The new tissues are I, cork cambium k, cork g, secondary phloem from the cambium, and just outside this is older crushed phloem , secondary xylem produced by the cambium m, secondary medullary ray made by the cambium (notice that this does not extend to the pith). Half of the pith is shown. Notice how it has been crushed almost out of existence. Compare Figs. 68 and 71, tissue for tissue, to find out what changes the primary tissues undergo with age, and to what extent new tissues are added. Photomicrograph x 20. (From Stevens.)...

Collenchyma is a form of ground tissue less frequently observed. It consists of living cells with additional cellulose thickening in the walls, giving them additional strength, and is most commonly found in the stem cortex. 

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