Aleurone layer protein bodies

Experiment 5. Observation under transmission electron microscope We compared the TEM ultrastructure of the seed coat and endosperm of control and rue-treated seeds The palisade layer of treated seed appears thicker than in the control (Figs 6A and 7A), while comparison between aleuronic cells of the control and treated cells (Figs. 6B and 7B), reveals that the cells of the control are healthy with some evident organelles such as the nucleus and the rough endoplasmic reticulum and other structures, the plastid, the plasmodesmata, conspicous constrictions, protein bodies and... 

Fig. 6 TEM micrographs of seed coat and aleurone cells of radish control seed 18 h after sowing in water e, epidermis pi, pigment layer al, aleurone layer. (A) Bar = 30 pm Particulars of the aleurone cell showing some organelles nucleus (n), plasmodesmata (pd), protein bodies (pb) and lipid droplets (Id). (B, C). Bar = 5 mm. 

The endosperm of members of the Gramineae and certain other species (e.g. Trigonella, Fagopyrum) is characterized by the possession of an outer aleu-rone layer. As the seed begins to mature, the peripheral cells of the endosperm which cut off cells internally begin to divide anticlinically to form small cells of rectangular appearance in section. One or more layers of such cells may be produced they become fairly thick-walled, develop protein bodies called aleurone grains and, most important, remain alive, unlike for example the other endosperm cells of cereals which are dead cells packed with starch and to a lesser extent protein. 

As outlined earlier (Chap. 2) reserve proteins are stored in two separate sites in the cereal grain in the aleurone grains (bodies) of the aleurone layer, and in the protein bodies (sometimes disrupted) of the endosperm. Proteolysis within... 

A phytase has been isolated from the protein bodies of whole, milled, ungerminated barley, and this enzyme appears to be associated with the protein bodies of the aleurone layer (aleurone grains), a known storage site of phytin [141]. There is strong evidence (e.g. in wheat and rice) against the association... 

The aleurone layer differentiates from the rest of the starchy endosperm approximately 2 weeks after pollination. There is clear evidence that aleurone cells synthesize starch granules after fertilization however, the starch granules disappear and the cell walls thicken as the grain matures. The cytoplasm of aleurone cells contains phytic acid bodies, protein bodies, and spherosomes or fat depots. The aleurone ceU walls contain soluble and insoluble dietary fiber, phenolics such as ferulic acid, ara-binoxylans, and P-glucans that fluoresce when viewed under a microscope equipped with ultraviolet light. 

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