CHAPTEK VI 



EFFECT OF BORON COMPOUNDS 



I. Prksence of Boron in Plants. 



The first claim to the discovery of boron in plants was put forward 

 in 1857 by Wittstein and Apoiger, who carried out investigations on the 

 Abyssinian Saoria (seeds of Maasa or Maessa picta, N.Q. Primulaceae^). 

 In the course of analyses a crystalline mass was obtained which was 

 found to contain chlorine, phosphoric acid, lime, and boric acid. The 

 discovery apparently attracted little attention and for about another 

 thirty years the matter was again allowed to sink into oblivion. Then 

 it came to the front again,, and from 1888 onwards one investigator after 

 another demonstrated the presence of boron in various plants. 



In 1888 Baumert detected boron in French, German, and Spanish 

 wines without exception, while E. O. von Lippman (1888) demonstrated 

 it in sugar must and also in the leaves and root of the sugar beet. In 

 the latter case the reactions were so definite that the presence of more 

 than a minimal amount of boric acid was conjectured. 



Crampton (1889) tested various fruits, but while he found boron in 

 every part of the watermelon, he could get no reaction with apples or 

 with certain samples of sugar cane. He predicted, however, that the 

 occurrence of boron would prove to be more general in the plant king- 

 dom than had previously been supposed. The next year (1890) Hotter 

 extended the work on fruits, testing for boron in the fruits, leaves, and 

 twigs of certain plants, and finding it in the apple, pear, cherry, raspberry, 

 fig, and others. His results indicated that fiiiits are relatively rich in 

 boron. Later on (1895) Hotter carried his experiments further, and he 

 stated that stone fruits are richer in boric acid than are berries and 

 pomes. The accumulation of boron is in the fruit itself, the other 

 parts of the plant containing little. The quantities of boric acid found 

 in the ash of the various fiiiits ranged from '58% in the "Autumn 



^ According to Engler'e olasBification this plant belongs to N.O. Myrtinaceae. 

 B. 5 



