ASH IN PLANTS I 5 



From the figures given in the foregoing tables we find that 

 the leaves of plants contain the most ash. The straws contain 

 more ash than the grains. 



Let us see the relation of the ash of roots to the leaves of the 

 same plant. 



The per cent, of ash in seeds is generally less than in the plant 

 from which they are derived. 



Ash Ash 



Per ceiit. Per cent. 



Sorgliuiu seed 2.1 Sorghum fodder 4.6 



Cowpea seed 3.2 Cowpea hay 7.5 



Soja beati seed •■ 4.7 Soja bean hay 7.2 



The per cent, of ash and the mineral elements that constitute 

 the ash are given for several vegetable substances in the follow- 

 ing table. ^ 



Occurrence of Mineral Elements in Plants. — According to 

 Forbes, Ohio Experiment Station Bui. 201 : "Mineral sub- 

 stances of foodstuffs are present in four mechanical conditions: 

 (i) in solution in the plant juices; (2) as crystals in the tissues; 

 (3) as incrustations in cells and (4) in chemical combination 

 with the living substance. 



"The mineral content of any species of plant varies con- 

 siderably as affected (i) by the composition of the soil and the 

 soil water, (2) by the various factors controlling transpiration of 

 water by the plant and (3) by the loss of mineral substances 

 either through shedding of parts or through the leaching effect 

 of dews and rains." 



Distribution of Ash in Plants. — Roots and seeds generally 

 contain much less ash than leaves because the mineral elements 

 are carried to the leaves for the elaboration (manufacturing) of 

 . food and then the water evaporates and the ash remains. The 

 ash present in roots and seeds is usually needed for supporting 

 germination and early growth of the plant, while some of that in 

 the leaves is in excess of what is really needed. 



1 Bui. 201, Ohio Experiment Station. 



