MORriiULUGY UF iiiGHER i'LAXTS. 



173 



Aleurone grains are made up of protein-er} stalloitls, globoids 

 and a ground mass, the whole being enelosed b\- a membrane- 

 like material. The}' may be studied by taking- advantao-e 

 of the difference in solubility of the substances composing them. 

 The membrane is a protoplasmic membrane and, while soluble 

 in water, remains intact on examining sections in any of the 



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Oo^. 



Fig. 97. Protein crystalloids: A, crll of tuber of white potato (Solanum iuberosu-it) 

 showing protein crystalloids (k), starch grains (st). nucleus (n): B, aleurone grains of the 

 seed of the castor-oil plant {Ricinus communis); C, aleurone grains of fruit of fennel 

 (Fceniculum vulgare) containing large calcium oxalate crystals (Ca) which are strongly 

 polarizing as shown in the isolated grains; D, aleurone grains of Brazil nut (Bertholletia 

 excelsd). g, globoids; k. protein crystalloids. 



fixed oils, as cotton-seed oil. L'suall\ seeds wdiich contain 

 aleurone are rich in fixed oils, and if this oil is first removed 

 by placing fresh sections in alcohol, or alcohol and ether, the 

 subsequent study is facilitated. If the sections thus treated 

 are mounted in water, the membrane gradually dissolves, leaving 



