A CHEMICAL STUDY OF THE ASPARAGUS PLANT. 275 



The relation of water to intensity of growth is clearly shown by the 

 changes in the proportion of water at the different stages of development. 

 The summer roots procured in the midst of the gromng season contained 

 more water than the dormant roots obtained the fall before. The tops 

 when just at their full height in midsummer were more watery than those 

 that were ripening in the foUomng October. But the most striking pro- 

 portion of water was found in the tender, succulent stalks of spring and 

 early summer at the period when growth is so rapid that it can be readily 

 measured from hour to hour. 



The active part performed by sugar is indicated by the difference in 

 the percentages of this substance found in the various stages of the devel- 

 opment of the plant. The large proportion of reducing sugar in the stalks 

 and tops at the successive stages sampled, and its absence from the differ- 

 ent series of roots, is in accord with distinction between active and reserve 

 forms of sugars. The sugar in the roots at the seasons chosen for their 

 study was wholly a reserve substance, and being readily soluble in water 

 passed unchanged toward the actively growing stallcs. 



The insoluble non-nitrogenous substances which form the bulk of the 

 plant at each stage of growth undergo the usual inverse changes in pro- 

 portion which accompany the increase and decrease of more active con- 

 stituents. 



Amino compoimds are an important part of the reserve nitrogenous 

 material in the fall roots, as their nitrogen forms almost one-half of the 

 total percentage of the element at that stage. This is a larger proportion 

 than at any other stage, and points to its probable value for rapid transfer 

 to the young stalks in the spring. 



The Inorganic Constituents op the Asparagus Plant. 



For comparing the progressive changes in the mineral constituents of 

 the different stages of the asparagus plant we have used the averages of 

 all results from the plots receiving complete fertilizers. 



At first sight the average composition of the three series of roots appears 

 to be practically alike, but a closer scanning reveals consistent variations 

 in some of the constituents from year to year. Calcium, sulfur and so- 

 dium steadily increased in percentages from stage to stage in the roots, 

 and also between the summer and fall stages of the tops. On the other 

 hand, potassium, magnesium and phosphorus varied between narrow 

 limits in the different stages of root development, and were noticeably 

 diminished in the final ripening stage of the tops. These three elements 

 are evidently translocated from the old tops to other parts of the plant, 

 while the three first mentioned go in only one direction and accumulate 

 as those parts of the plants grow older. 



Sulfur is considerably in excess of phosphorus, which is unusual in our 

 common garden crops. While no provision was made for this in planning 

 the fertilizer, there was apparently enough of the element present in the 

 stable manure or superphosphate used. 



