GRASSES OF IOWA. 83 



on the dorsal side of the scutellum. It was also found that 

 this corrosion of starch took place last of all in the groove. 

 Haberlandt therefore concludes that the scutellum as well as 

 the aleurone layer are secreting organs. To test this work, 

 Haberlandt removed portions of the testa, including the aleu- 

 rone layer, which had germinated to a certain degree. The 

 second was washed with a brush containing one to two per 

 cent sugar solution, placed upon moist filter paper with the 

 aleurone layer upward. Upon the aleurone layer was placed 

 a small quantity of moistened rye meal. The whole was then 

 kept moist at a temperature of 18 to 20 C. In a couple of 

 hours a corrosion of the starch grains had taken place. These 

 sections were compared with others not so treated. In order 

 to demonstrate this, Haberlandt cut around the edge of the 

 scutellum and found that notwithstanding the break in the 

 continuity of the aleurone layer and its complete separation 

 from the embryo, it did not prevent the spread of the diastatic 

 action, when these were later germinated. The inactive aleu- 

 rone cell, according to the same investigator, contains no 

 appreciable amount of diastase. 



Brown and Morris, who . investigated this question, state 

 that they were at first inclined to believe as Haberlandt does, 

 that the progressive action of the corroded starch grains were 

 due to the special action of the aleurone cells. They further 

 stated that the true explanation is due to the solution of the 

 cell walls of the starch containing endosperm, but that this is 

 a necessary prelirninary to the dissolving action of the starch. 



J. Gruss, * from a series of experiments on corn and several 

 other plants, concludes that there exists in the germinated 

 seed a soluble diastase which is capable of diffusion through 

 the cell wall in the same way that sugar does. The removal 

 of the cotyledons diminishes the amount of diastase in the 

 stem. Brown and Morris state they found that the mother 

 substance of the diastase secretion is probably derived from 

 the endosperm. Tne form in which reserve starch enters the 

 growing embryo has been found to be mostly invert-sugar, but 

 there is also a considerable amount of cane sugar, as Kuhne- 

 mannf has shown. Later KjeldahlJ found that cane-sugar is 



♦Pringsheim Jahrb. t. wlss. Bot. 26: 379-437. pi. 2. 1894; Ber. Deutsch. Bot. GeseU. 13: 

 2-13. pi. 1 . 1895. 



+Ber. Chem. GeseU. 8: 202-387. 



$RSsum6 du Compt rend des travaux du Laboratoire de Carlsberg. 1881 : 189. 



