IMPORTANCE OF LIME SALTS. 



39 



Church's investigations" with albino leaves demonstrated that the 

 composition of their ash is very different from the ash of healthy 

 leaves, as the potassa is considerably increased in the white leaves, 

 while on the contrary the lime is more abundant in the green leaves. 

 It is to be regretted, however, that the author did not determine sepa- 

 rately the amount of lime present as oxalate and carbonate and that 

 portion of the lime belonging to the organized matter itself, calculat- 

 ing the results for equal surfaces in both cases. It is also very char- 

 acteristic that the lime content of the phanerogamic parasite Cuscuta, 

 which forms no chloroplasts in the full-grown state, amounts to only 

 2 per cent in tin 1 ash, while the clover, its host, is very rich in lime. 



Another interesting case, showing a decrease in lime content in dis- 

 eased leaves, was observed by Dr. Erwin F. Smith in his studies of 

 peach yellows. He gives the percentage of lime in the ash of the 

 health}' leaves, according to analyses made by Mr. N. E. Knorr, as 

 4<>.58, and in the diseased leaves as only 23.88. b According to a later 

 analysis, made by Dr. Eastwood at Dr. Smith's request, the ash content 

 of healthy twigs of one season's growth is given as 2.10 to 2.58 per cent 

 and that of diseased twigs as only 1.0 per cent, and of healthy twigs 

 from another orchard as 1.1 per cent and of diseased twigs as only 1 per 

 cent.'* In these eases the amount of lime was also less in the diseased 

 leaves, while potash, magnesia, and in most cases phosphoric acid 

 also were relatively increased, as will be seen from the following table: 



Analytical <hil<i from diseased mul healthy trees from four orchards. 



[Per cents in the ash.] 



The observations which' Honda and the writer' 7 made with young 

 pine trees transplanted to pure quartz sand moistened with culture 

 solutions free from lime have shown that the new leaves reached only 

 half their normal size, and that the young trees gradually perished. 



"Jour. Chem. Soc, 1878 and 1886. The investigations were made with Quercus 

 rubra bearing some albino branches, and also with albino leaves of Plectogyne varie- 

 gata and of Hedera helix. 



''Erwin F. Smith, Bull. No. 4, Division of Botany, U. S. Dept. of Agriculture. 



c Erwin F. Smith, Bull. No. 4, Division of Vegetable Physiology ami Pathology, 

 U. S. Dept. of Agriculture 



dBull. Coll. of Agr., Tokyo, Vol. II, No. (». 



