Bagley, Bill W., Joe H. Cherry, Mary L. Rollins, and Aaron M. Altschul. (Southern Regional Lab., U.S.D.A., New Orleans, La.) A study of protein bodies during germination of peanut (Arachis hypogaea) seed. Amer. Jour. Bot. 50(6) : 523–532. Illus. 1963.—Upon germination of peanut seed (Aracs nypoyaea) there is an ordered series of events leading to the degradation of storage protein in cotyledonary cells. In resting seed, the protein is stored in large bodies (protein bodies) about 5–10μ in diameter. As the seeds germinate, the protein bodies swell and develop cavities within. Later these swollen bodies break up into many fragments which are digested and disappear. The major changes in proteins as revealed by microscopy and by protein analysis occur between 4 and 9 days of germination. By 15 days, the parenchyma cells are empty of protein bodies or fragments, but they contain many small starch grains. In a given cell population, there is a wide range of protein‐body degradation, the degree of degradation being related to the distance from the nearest vascular bundle. In resting seed, there is a honeycomb‐like structure between and connected to the subcellular particles. After 2 days of germination this structure is no longer visibly intact.
A method is described for comparing microscopically the cross-sectional areas of the same cotton fiber in wet and dry conditions, for evaluation of swelling. Results indicate the change in cross-sectional area of raw cotton fibers to be between 21 % and 34% of the dry area regardless of variety of cotton or degree of maturity of the fiber. Immature samples show slightly less mean swelling than mature samples, but this is believed to be due to the presence of fibers with no secondary thickening at all which tend to shrink in cross-sectional area rather than swell. In the immature fibers deformation (defined as change in circularity) is slightly more than that of mature fibers. This, coupled with the fact that in a given weight of immature fibers there are approximately twice as many fibers as in a like weight of mature fibers, helps to explain the greater closing capacity of yarns made from immature cotton. Flax and a sample of viscose rayon show twice the swelling of cotton, Fortisan two-thirds as much, and nylon no crosssectional swelling at all.
Untreated and chemically modified cotton fabrics which had been laboratory-abraded by machine-washing and tumlledrying were studied with the scanning electron microscope. Generally, abrasion patterns were not different from those normally associated with any wet or dry abrasion. Greater differences were observed between washing machine-abraded and dryer-abraded samples than between treated and untreated samples abraded by the same method.
The primary wall of fully matured cotton fibers has been isolated and its morphology and composition studied by electron microscopic examination and by chemical analyses. The pri mary wall appears to contain about 50% cellulose; protein, wax, and pectic substances occur in lesser amounts; cutin or suberin and mineral matter are also present. The concentration of noncellulosic substances in the primary wall is much greater than in the whole fiber. Electron microscopic examination of the primary wall indicates that it consists of a network of cellulose fibrils, having diameters of 100-400 Å, surrounded by the noncellulosic constituents. The oriented fibrillar systems observed with the polarizing microscope have not been seen in the electron micrographs of the specimens studied. There is an apparent increase in the diameter of the fibrils of the primary wall and in the denseness of the network as the fiber matures. The existence of layers in the cellulose network has been observed.
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