C 35 ] 



IV. 



THE ABSORPTION OF WATER BY SEEDS. 



By W. R. GELSTON ATKINS, B.A., 

 School of Botany, Trinitj^ College, Dublin. 



[communicated by professor H. H. DIXON, D.SC, F.R.S.] 

 [Read December 22, 1908. Ordered for Publication January 12. PuUished Mauch 16, 190 9.] 



This paper describes an attempt to discover the forces -wliich cause water 

 and salt solutions to enter dried seeds, in the hope tliat some light might 

 be thrown on the condition of latent life existing in them. Experiments 

 were also conducted with a view to ascertaining when the evolution of 

 CO3 began in moistened seeds; and the density changes involved in the 

 moistening were incidentally examined. 



The experiments were carried out on two main lines, first by weighing 

 the seeds used at intervals after immersion in water or salt solutions, and 

 thus determining the increase in weight, and also the permeability of the 

 seeds ; secondly, by adding volumetric solutions to seeds, and noting any 

 change in concentration that might occur. The latter was the method 

 adopted by A. J. Brown in his investigations on Hordeum, when he proved 

 that the spermoderm functioned as a semipermeable membrane.^ 



Throughout this paper the term " living " is used of seeds in the con- 

 dition of latent life, when all metabolism is at a standstill, but may be set 

 in motion under suitable conditions. Germination is tlie only true proof of 

 the existence of latent life in any seed ; the evolution of CO2 is not a proof, 

 as will be shown later. 



Weighing Method. 



Seeds of Phaseohis vulgaris (Linn.) and Lathynis odomtus (Linn.) were 

 immersed in pure water, gram-molecular, and saturated potassium nitrate, 

 and in almost saturated water-vapour. They were weighed at intervals till 

 no further absorption took place, tlie temperature being maintained constant 

 to within a degree by a thermostat. 



The seeds used were desiccated by drying at 28° C. for some days, then at 



' Ann. Bot., xxi., 1907, p. 81. 

 SOIENT. PBOC. R.D.S., VOL. XII., NO. IV. H 



