160 FUNDAMENTALS OF FRUIT PRODUCTION 



likewise marked increases in yield from its application to cocoanuts.'^^ 

 To what extent these increases were due to direct or indirect effects of the 

 sodium Or the direct or indirect effects of the chlorine is not known. 



Alumintun and Manganese. — Manganese is a common constituent of the 

 bark, where it seldom exceeds 1 per cent, of the ash. The other parts of the 

 tree usually have less than the bark. Aluminum and manganese combined 

 average 0.5 to 0.9 per cent, of wood ash. Aluminum is not uncommon in seeds. 

 It sometimes comprises 0.062 per cent, of the ash of fig seeds and 0.138 per cent, 

 of the ash of almonds.'*^ Aluminum is capable of forming complex salts with 

 the anthocyan pigments." The color of the pigment depends on the base which 

 it contains, which accounts for the fact that the hydrangea {H. hortensis) develops 

 blue instead of pink flowers when soluble aluminum compounds are applied to 

 the soil in which it grows. "^ 



Summary. — Certain elements, especially nitrogen, phosphorus, potas- 

 sium and sulphur are present in greatest amount in young tissues. Cer- 

 tain amounts are stored in the bark over the winter and in the spring a 

 supply is on hand for the rapid development of leaves and shoots, flowers, 

 fruit and seeds. Since the seeds themselves are storage organs and in addi- 

 tion contain embryonic tissue, they accumulate these elements in relatively 

 large proportions. Magnesium and iron likewise are stored in the bark 

 and in the wood as well. They are utihzed in new growth, though they 

 appear to be more equally distributed in mature and in embryonic 

 tissues. All of these elements show more or less mobility and are trans- 

 located to regions where they are more in demand. The plant con- 

 serves its supply and withdraws at least a part of the amount contained 

 in the leaves, after they have ceased to function. 



Calcium and silicon are very nearly absent from embryonic tissues. 

 They accumulate throughout the plant with age. There are no indica- 

 tions that these elements are stored for future use and to a great degree 

 they remain where they are deposited. 



With respect to the other mineral elements found in plants, little 

 can be said in generalization. This is because no regularity has been 

 observed in the amounts present or in their seasonal variation. 



