Sclerenchyma fibers

Wardrop (13,14) examined sclerenchyma fibers of Liriodendron tulip-ifera and sclereids of Pyrus communis, previously fixed with KMn04, and concluded that the vesicles supplied their contents to the cell wall, though the origin of the vesicles was not established. As discussed before, however, permanganate fixation is undesirable for these cytological observations. 

Crystal fibers are longitudinal rows of superimposed parenchyma cells each of which contains a single monoclinic prism or rosette aggregate. Crystal fibers are found adjacent to sclerenchyma fibers such as bast or woody fibers. 

Fig. 43,—Sclerenchyma fibers from different sources, i, Prom powdered cinnamon bark 2, End of bast fiber of flax stem showing transverse markings (6) 3, middle portion of flax fiber showing characteristic cross markings at b 4, bast fiber from cinchona bark 5, branched bast fiber from choke cherry bark 6. above, end, and below, median portion of bast fiber of jute. All highly magnified.

Bast fibers Wood fibers Sclerenchyma fibers Stone cells Collenchyma... 

Pig. 8o.—Photomicrograph of a representative portion of Greenbrier stem showing epidermis (,e.p.), cortex (c), endodermis (e.n.d.), cylinder sheath (c.s.), sclerenchyma fibers of closed collateral bundle ( ), fundamental parenchyma (J.p.), trachea (/). X 22. 

V. Drupaceous Fruits (Succulent fruits in which the mesocarp is more or less succulent, but the endocarp leathery or stony).— A Drupe is a one-celled, one-seeded drupaceous fruit such as the fruit of the Plum, Peach, Prune, Sabal, Rhus, Piper, Cherry, etc., whose endocarp or putamen is composed wholly of stone cells or stone cells and sclerenchyma fibers. Fig. 103 (i). 

Ten pages have been added to Chapter V on Cytology. Under Protoplasm and its Properties, six pages have been written on the subject of Irritability and Irritable Reactions. Under Non-Pro toplasmic Cell Contents several additional commercial starches are discussed and two original plates on starch grains added. Additional cuts on Collenchyma, Stone Cells, Sclerenchyma Fibers, Trichomes and Fibrovascular Bundles have been inserted in Chapter VI. 

Wood fiber (type of sclerenchyma cell) Larger, more slender than the tracheid tapering heavy wall thickening and lignification pits are reduced in size and number relative to tracheids Protoplast lost as cell attains maturity Strength... 

Wheat straw is composed of different tissues that are more or less destroyable during the process. Leaves, intemodes, and the parenchyma (see Fig. 17.4) are more particularly destroyable. The sclerenchyma and the fibers networks are more resistant. 

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