466 



THE SEED AND ITS GERMINATION. 



1211. The time required after planting for germination to 

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

 been determined l 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. 2 



The unqualified statement found in some works, 3 that light is 

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



1213. The 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 4 



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

 Inst., 1884. 



2 Hoffmann : Jahresber., liber Agricultur-Chem., 1864, p. 110. 



3 Ingenhousz ; Senebier, Physiologic vegetale, iii. 1800, p. 396 ; Johnston's 

 Lectures on Agricultural Chemistry, 1842, p. 194. 



4 Mliller : Botan. Unters. ii., 1872, p. 29, quoted by Nobbe (Hand- 

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

 gave results somewhat lower than this. 



