69 



Further Observations on the Germination of the Seeds of the 

 Castor Oil Plant (Biennis communis). 



By J. Reynolds GREEN, Sc.D., F.K.S., Professor of Botany to the Pharma- 

 ceutical Society of Great Britain, and Henry Jackson, M.A., Fellow 

 and Tutor of Downing College, Cambridge.* 



(Received March 22,— Eead May 18, 1905.) 



About 15 years ago one of the authors carried out a series of researches 

 on the germination of the seeds of the castor oil plant {Bicinus communis),^ 

 and endeavoured to ascertain the course of the decomposition and utilisation 

 of the reserve materials which are present in the seed. As the results 

 of this investigation formed the starting point of the present series of 

 researches, it will be well at the outset to restate the conclusions which 

 were then arrived at. 



The larger part of the reserve materials of the seeds of Bicinus, which 

 are laid up in the cells of the endosperm, consists of the well-known castor 

 oil. The amount varies in different seeds, but it ranges from as little as 

 50 per cent, to upwards of 80 per cent. There is a considerable amount 

 of proteid matter in the cells, most of which is found in the so-called 

 aleurone grains. These have a somewhat intricate structure ; an ovoid 

 mass of phytoglobulin, soluble in 10 per cent, solution of common salt, 

 surrounds a proteid crystal, soluble in saturated solution of the same salt. 

 In the grain by the side of the crystal there is a rounded aggregation of 

 mineral matter, the so-called globoid, long considered to be a double 

 phosphate of calcium and magnesium, but probably a more complex body 

 containing its phosphorus in some form of organic combination. According 

 to Vines % the proteids of the grain are an albumose and a globulin; 

 in the opinion of Osborne and Harris § this is not the case, only a globulin 

 being present, probably identical with the edestin of the hemp seed. There 

 are other substances present in small amount, but in very trifling pro- 

 portions when compared with the oil and the proteids. 



* The present series of experiments was commenced by rne in collaboration with 

 Mr. W. T. N. Spivey, of Trinity College, Cambridge. After his lamented death in 1901, 

 Mr. Jackson took his place. — J. E. G. 



t Green, ' Eoy. Soc. Proc.,' vol. 48 (1890), p. 370. 



% Vines, "Proteid Substances in Seeds," ' Journ. of Physiol.,' vol. 3 (1880), p. 91. 

 § Osborne and Harris, " Nitrogen in Protein Bodies," ' Amer. Chem. Journ.,' vol. 25 

 (1903), p. 335. 



