54 



DEPARTMENT OF AGRICULTURE GEORGIA. [340] 



WATER IN FRESH PLANTS. 



Per Cent. 



Meadow Grass 72 



Ked Clover 79 



Maize, as used for fodder. . 81 



Cabbage 90 



Potato Tubers 75 



Sugar Beets 82 



Carrots 85 



Turnips 91 



Pine Wood 40 



WATER IN AIR- DRY PLANTS. 



Per Cent. 



Meadow Grass (Hay) 15 



Red Clover Hay 1 



Pine Wood 20 



(Straw and Chaff of Wheat, 



Rye, etc 1 



Bean Straw 18 



Wheat, Rye, Oat, (kernel) 14 

 Maize (kernel) 12 



Since no mineral substance can be taken into the plant 

 except in a state of solution, it is not only necessary that 

 there should be an abundance of moisture in the 

 that the mineral elements of plant-food shall be in a solu- 

 ble condition before they can be made available to the 

 plant. The water in the soil enters the absorbing surfa^ 

 ces of the roots of the plants mainly by osmodic imbibi- 

 tion, certain vegetable acids being expelled by exosmose 

 from the root-hairs, which act chemically upon the mineral 

 substances of the soil, as is plainly shown by the etching 

 of smooth marble by the roots of plants which rest upon 

 it during their growth. Capillary force may also partici- 

 pate in this imbibition, when a rapid evaporation of watery, 

 vapor is progressing from the surfaces of the leaves. 



This liquid, (soil water,) freighted with unorganizable or 

 crude plant-food^ passes by osmodic action from cell to 

 cell, until millions of these receptacles have been traversed 

 in its passage to the leaf where, spread out under the in- 

 fluence of sunlight, it is assimilated converted into more 

 condensed organizable plant-food by the evaporation of 

 watery vapor, and the exhalation of oxygen. 



The contents of the cells of the leaves being thus ren- 

 dered more condensed, the prepared sap passes down- 

 ward from cell to cell, is appropriated to the growth of 

 the plant by cell division over the entire growing surface 

 of the plant, thus perpetuating the process so long as the 



