14 
observed in the percentages of the mineral elements in a given species 
of plant when grown under different environments, such as are 
afforded by different types of soil, climatic variations and lati- 
tudinal changes, and the exact significance of the variations thus 
induced isnot fully understood; but the variations in the compo- 
sition of pineapple ash, herein reported, especially as regards the 
lime, magnesia, and phosphorus pentoxid, are believed to have spe- 
cial importance. The significance of these data has been fully inter- 
preted in a previous publication which is devoted to a comprehensive 
study of the function of manganese in plant growth. 1 
At this time it is wished merely to call attention to the excessive 
amounts of lime and the relatively smaller amounts of magnesia, as 
well as a correspondingly smaller percentage of phosphorus pentoxid, 
in the plants from manganiferous soils. As previously mentioned, 
the occurrence of calcium oxalate crystals is much more abundant in 
the chlorotic plants; in fact the presence of calcium oxalate forms 
one of the noticeable characteristics in all parts of these plants ; and 
while this so-called by-product occurs in considerable amounts in 
normal pineapple plants, the amount is in great excess in the chlo- 
rotic plants. Various authorities have discussed the occurrence of 
calcium oxalate in plants, and in general they are agreed that one of 
the functions of lime in plants is to neutralize the acids formed as 
a result of metabolism. One of the principal acids thus formed is 
oxalic, which has been supposed, by various authorities, to result from 
at least two different sources: (1) It may arise from a decomposition 
of carbohydrates during plant respiration; and (2) it is thought to 
be derived, in some instances, from the breaking up of protoplasm. - 
In chlorotic pineapples there have been observed a general disin- 
tegration and breaking up of the organized structure of the proto- 
plasm and the complete disappearance of the chloroplasts. With 
this there is a simultaneous appearance of oxalate of calcium. From 
these observations the conclusion may be drawn that the excessive 
amount of oxalic acid in chlorotic pineapples results from a decom- 
position of the protoplasm itself, and that its neutralization and sub- 
sequent crystallization is made possible through the presence of 
abnormal amounts of lime in the cell sap. 
THE RIPENING OF THE PINEAPPLE FRUIT. 
As has been clearly shown by numerous chemical analyses made at 
this station, it is a peculiar feature of the ripening of the pineapple 
fruit that no increase in the amount of sugar takes place during the 
ripening process if the fruit has been removed from the plant. It 
is apparent, therefore, that the materials which are transformed into 
sugar are to be sought in other parts of the plant than the fruit. 
i Hawaii Sta. Bui. 26. 
[Bull. 28] 
