466 



THE SEED AND ITS GEKMESTATION. 



1211. The time required after planting for germination to 

 begin, a point indicated by the protrusion of the radicle, has 

 been determined ^ for a large number of plants. A few exam- 

 ples are here mentioned : — 



1212. The influence of light upon the earliest stages of germi- 

 nation has been shown by careful investigations to be inappre- 

 ciable so far as most plants are concerned.^ 



The unqualified statement found in some works/ that light is 

 in general prejudicial to germination, is not borne out by facts. 



1213. TMe phenomena of germination are : (1) forcible absorp- 

 tion of water, (2) absorption of oxygen, (3) solution of nutrient 

 matters, (4) their transfer to points of consumption, (5) their 

 employment in building up new parts. After the initial step 

 these processes may go on simultaneously. 



1214. The enormous imbibition power of dry seeds can be 

 demonstrated by confining sound seeds in a strong receptacle 

 to which water can obtain access. If a closed manometer is 

 attached, the pressure they exert can be measured. Boehm * 



1 Versuchs-Stationen, xvii., 1874, p. 104 ; and Storer : Bulletin Bussev 

 Inst., 1884. •' 



2 Hoffmann : Jahresher., iiber Agricultur-Chem., 1864, p. 110. 



3 Ingenhousz ; Senebier, Physiologie vdgetale, iii. 1800, p. 396'; Johnston's 

 Lectures on Agricultural Chemistry, 1842, p. 194. 



4 Muller: Botan. Unters. ii., 1872, p. 29, quoted hy Nobbe (Hand- 

 buch der Samenkunde, p. 118). Similar experiments at Welleslev College 

 gare results somewhat lower than this. ° 



