116 GERMINATION. 



of the action of the oxygen on the carbon of the seed. This may 

 be witnessed in the germination of large masses of Barley. 



2C8. The most important change produced in germination on 

 the contents of the seed is the conversion of the amylaceous 

 portion into sugar. This is through the action of Diastase. 

 This substance is produced at the commencement of germina- 

 tion, and the sole object of its production seems to be the con- 

 version of starch into sugar for the use of the embryo plant. It 

 • iocs this with the greatest promptness; even when artificially 

 obtained it will convert two thousand times its own weight of 

 starch into sugar. It is perfectly inert in relation to any other 

 vegetable product. Its situation in the grain would lead us to 

 suppose that its operation was of the character above assigned 

 to it. It does not exist in the radicle, or in the cotyledons of 

 the seed, but immediately in the passage from the cotyledons to 

 the germ. It also exists in tubers, as the potato, and in them 

 it is not distributed throughout the substance, but only at the 

 v- tv origin of the eyes, precisely at the place where one would 

 conceive it to be placed to dissolve the amylaceous substance for 

 the nourishment of the growing organs. This is an exceedingly 

 important discovery in relation to vegetation, as it carries us one 

 step further into the mysterious operations of nature, as exhibited 

 in the nourishment and growth of vegetables. 



209. The time required for germination is very different in 

 different species of plants, and even of the same species. Much 

 influence also is exercised over this operation by soil, climate, 

 and localities as to moisture and exposure. 



Under favorable circumstances, Wheat, Oats, Rye, and Millet, 

 will germinate in one day ; Spinage, Bean, Turnip, Radish, 

 Mustard, in three days; Lettuce in four days ; Melon, Cucum- 

 ber, tfec, in Jive days ; Horse-radish in six — Barley in seven — 

 Purslain in nine — Cabbage and Hyssop in ten — Parsley in 

 fourteen or fifteen ; Almond, Peach, Peony, in a year ; Rose, 

 Hawthorn, two years. These results will vary from the age of 

 the seed before exposure to the agents that produce germination, 

 and the influences to which it has been exposed, whether its 

 vitality may have been injured by moisture, heat, or light, all of 

 which exen ise a deleterious influence on seeds. 



210. The time through which seeds will retain their vitality 

 is rery different in different species, when exposed to the same 



208. What i* the most important change I Through the action of what? 

 When produced! How much Btarch will it convert into sugar ? "When 

 produ aid of the time required for germination? 



Mention some examples. — 210. What of the time seeds will retain their 

 vitality ? 



