228 Physiological Pre-determination 



development of the plant of the removal at an early stage of the endo- 

 sperm of albuminous seeds are in the main quite similar to those that 

 occur in the case of exalbuminous seeds deprived wliolly. or in part, of 

 their cotyledons. 



J. A. Urbain(3G) in 1913 carried out experiments with oats, maize, 

 fennel, Saponaria s^.,Nigella hispanica, Papaver somniferum, and Ricitius 

 cojiunams. As in the case of Delassus' experiments, this author found 

 that the effects produced as the result of removal of the seed-reserves 

 were not merely temporary, from which the plant might recover after 

 it had become established, but persisted throughout the whole course 

 of its development. In all the species tested the effects were the 

 same in character; the suppression of the endosperm (or perisperm) 

 led to a dwarf habit, obvious modifications in the external mor- 

 phology of the leaves, precocious flowering, sometimes followed by a 

 second flowering, and frequent sexual anomalies in the course of the 

 first flowering period. 



It is of interest to record in some detail a single experiment of Urbain's 

 in illustration of his results. Embr3^os of Riciniis communis were isolated 

 from their food-reserves on the second day of germination and were kept 

 in a greenhouse at 25° C. until the 12th day, when they were "potted 

 out." On the 35th day they were transplanted to open ground together 

 with controls. On the 47th day the controls were 1 metre in height 

 whereas the experimental plants were only |- metre in height. The 

 controls had the usual 9-lobed leaves, but the leaves of the treated 

 plants possessed only 4 lobes. Flower spikes had appeared in the axil 

 of the 4th leaf only in the case of the treated plants, the male flowers 

 on these flower-spikes exhibiting various abnormalities. During this 

 flowering period the growth of the treated plants was arrested, but 

 the plants subsequently continued their growth. About the 74th day 

 the controls produced flowers, and at the same time the plants from the 

 treated seeds produced a second crop of flowers, the controls being at 

 this stage 2 metres high as against | metre in the case of the experimental 

 plants. 



Results of a similar nature were obtained with the other albuminous 

 seeds investigated by Urbain (e.g. oats, maize, fennel, etc.). 



Consideration of the above experiments, both of the earlier German 

 agriculturists and of the more recent French school, strongly suggests 

 that the influence exercised upon the plant throughout its development 

 by the food-reserves of the seed is a phenomenon which needs further 

 examination. 



