116 Mary Gordon : Endosperm in Cereals. 



Summary. 



(i) The first formed endospermic cells of cereals are derived 

 from the secondary nucleus of the embryo-sac. 



(2) The nuclei so formed pass to the walls of the embryo- 

 sac, when they form a lining layer. Later the nuclei become 



•enclosed by cell walls, so that the embryo-sac is lined by a 

 single layer of cells. 



(3) The lining layer of the embryo-sac assumes the character 

 of a cambium, which produces segment cells only on its inner 

 surface. 



(4) The segment cells formed by the division of the cambial 

 cells enlarge, remain thin-walled, and become packed with 

 istarch, to form the starchy endosperm. 



(5) After the cells of the endospermic cambium have ceased 

 to divide, they become filled with aleurone grains and the cell- 

 walls thicken. It then forms the aleurone layer. 



(6) The greater respiratory activity of the aleurone layer and 

 the presence of vitamines in it are the natural results of its 

 being a resting cambium. 



(7) Whether it can be awakened to further activity during 

 •germination remains for future investigation. 



The foregoing research was carried out in the Botanical 

 Department of Melbourne University, under the direction of 

 Professor Ewart, and represents the work done as Caroline 

 Kay Scholar. 



References. 



(i) Ernst and Bernard — Annales du Jardin Botanique de Buit- 

 •enzorg (Ser, 2) 10, 1912. 



(2) McLennan, E. — Proc. Roy. Soc. Victoria, vol. xxxii., 

 1920, p. 252. 



(3) Brenchley, W. — Annals pf Botany, vol. xxiii., 1909, p. 117. 



(4) Brenchley, W. — Annals of Botany, vol. xxvi., 1912, p. 903. 



(5) Collins, E. J. — Annals of Botany, vol. xxxii., 1918, p. 381. 



(6) Steward — Annals of Botany, vol. xxii., 1908, p. 415. 



(7) Chick and Hume — Royal Society of London, 191 7, vol. 



-903, P- 44. 



(8) Brown and Morris — ^Journal of the Chemical Society, vol. 

 Ivii., 1890, p. 458. 



(9) Haberlandt — Physiological Plant Anatomy. 



