Microstructure of Produce Degradation 531
FIGURE 18.2Schematic drawing of a plant cell. Amyloplast, starch-storing plastid; Chro-
matin, deoxyribonucleoprotein fibrils; Chloroplast, double-membrane-bound organelle with
photosynthetic lamellae; Cell wall, rigid extracellular layer composed of microfibrils in a
matrix; Cytoplasm, the fluid matrix and associated molecules between the vacuole and the
cell wall; Dictyosome, membrane system of a few disc-shaped cisternae with secretory
vesicles. The golgi apparatus is the cell’s whole complement of dictyosomes; Endoplasmic
reticulum, flattened cisternae and tubules of membrane sometimes with attached ribosomes;
Intercellular space, the space formed at the junction of three or more adjacent cell walls;
Mitochondrion, a cell organelle responsible for cellular respiration; Microfibril, the cellulose
strands of the cell wall, having a diameter of 10 to 30 nm; Middle lamella, a more darkly
staining zone between adjacent cells, rich in pectin; Microtubules, 20-nm-wide tubules that
may be involved in movement in the cytoplasm; Nucleus, a double-membrane-bound com-
partment enclosing the chromosomes, nucleolus, and nucleoplasm. The envelope has nuclear
pores; Plasmodesmata, intercellular cytoplasmic connections; Plasmalemma, cell membrane;
Pinocytotic vesicle, an “infolding” of the cell membrane; Spherosome, single-membrane-
bound vesicle with stainable contents; Tonoplast, vacuole membrane; Vacuole, aqueous,
membrane-bound area within the cytoplasm; Vesicle, membrane-bound cytoplasmic inclusion.
(Adapted from Jewell, G.G., Fruits and vegetables, in Food Microscopy, Food Science and
Technology, Vaughn, J.G., Ed., Academic Press, New York, 1979.)