go PHARMACEUTICAL BOTANY 



ALEURONE GRAINS 



Aleurone grains are small bodies found in seeds particularly those 

 containing oil, and like starch grains often are characteristic of the 

 genus or species. Each aleurone grain consists of a ground sub- 

 stance (composed of amorphous proteid matter soluble in water, 

 dilute alkali or acid), in which are usually embedded one or more 

 phyto-globulins (insoluble in cold water, but soluble in less than i per 

 cent, solution of an alkali, in dilute HC1 and acetic acid), one or more 

 transparent globular globoids composed of Ca and Mg phosphate 



PIG. 39. To show aleurone grains. A , cells from cotyledon of seed of garden 

 bean; n, aleurone grains; m, starch; B, cells from endosperm of castor bean; a, 

 a, aleurone grain; I, ground substance; k, phytoglobulin; I, globoid. (A, After 

 Sachs; B, after Frank.) 



(insoluble in water and dilute potash solution but soluble in i per 

 cent, acetic acid solution), and frequently a crystal of calcium 

 oxalate, the whole being enclosed by a protoplasmic membrane (so- 

 luble in water). (Fig. 39$.) 



The proteins insoluble in the cell-sap water are made soluble for 

 translocation by means of proteolytic enzymes which change them 

 into proteoses and peptones. 



20. Mucilages and gums are those substances occurring in plants 

 which are soluble in water or swell in it, and which are precipitated 

 by alcohol. 



Mucilage is formed in plants in several ways, viz.; either as a 

 product of the protoplasm, as a disorganization product of some of 

 the carbohydrates, as a secondary thickening or addition to the cell 

 wall, or as a metamorphosis of it. In the first two cases the mucilage 

 is called cell-content mucilage; in the last two, membrane mucilage. 



