Depletion of Endosperm of Hordeum vulgare. 3 



<; On the Depletion of the Endosperm of Hordeum vulgare 

 during Germination." By HORACE T. BROWN, F.R.S., and 

 F. ESCOMBE, B.Sc., F.L.S. Received December 11, 1897, 

 Read March 3, 1898. 



[PLATE 1.] 



In an account given by one of us in 1890 of the results of an 

 investigation of the histological and physiological changes which 

 take place in the seeds of the Grasses during germination,* a pro- 

 minent position was given to a discussion of the relations existing 

 between the endosperm and embryo, and to the part played by each 

 in the preparation of the reserve materials of the seed for the 

 nutrition of the young plant. This branch of the inquiry was 

 much facilitated by the discovery that the embryo, when separated 

 from the other parts of the seed, is capable of an independent 

 existence, providing it is supplied with a suitable artificial nutri- 

 ment in the form of certain carbohydrates, its own store of pro- 

 teids being sufficient to supply the nitrogen requisite for the 

 production of young plants of a considerable size. 



The carbohydrates most favourable to rapid growth in such cases 

 are sucrose, dextrose, and maltose ; but it was also found that the 

 embryo, when deprived of such readily assimilable material, acquires 

 the power of dissolving solid starch to a very notable extent, a 

 function which was subsequently localised in the columnar epithe- 

 lium of the scutellum. 



The endosperm itself was also subjected to examination with a 

 view to determine if it possesses any power of acting on the reserve 

 materials contained within its cells, and of bringing about any 

 self-depletion which is independent of the influence of the embryo. 



This question was attacked in two different ways. In the first 

 place, endosperms, after being degermed, were placed under favour- 

 able conditions for the full play of any metabolic activity which 

 might be possessed by any portion of their tissue, every facility 

 being afforded for the rapid outward diffusion of the products of 

 change ; and, secondly, advantage was taken of a fact which had 

 previously been established, that an embryo may be transferred 

 from one endosperm to another without materially affecting its 

 power of subsequent growth ; thus affording an opportunity of 

 subjecting an endosperm to such treatment as may reasonably be 

 supposed capable of destroying any residual vitality in its cells, 

 and of then observing how this affects the subsequent development 

 of a fresh embryo " grafted " upon it. 



For the full details of these experiments we must refer to the 



* Brown and Morris, ' Chem. Soc. Journ.,' vol. 57, p. 458. 



B 2 



