DEPARTMENT OF BOTANICAL RESEARCH. 



63 



Five successive series of tests were made of different samples of these tissues, 

 and the results are averaged in table 1. 



Table 1. — Relative swelling of stem-tips of blackberry in salt 

 solutions compared to that in water as unity. 



The relative effects of potassium, sodium, and calcium chlorides is the 

 reverse of that with walnut. Potassium permits the greatest swelling of 

 blackberry, nearly twice as much as in water. The results with sodium and 

 calcium were peculiar in these tests. The tissues consistently shrank when 

 first immersed in the sodium-chloride solutions and in calcium chloride of 

 less than 0.01 M concentration. The shrinkage was very prompt and con- 

 tinued only about 15 minutes, then, swelling quickly, brought the tissues 

 to more than the initial thickness. Calcium chloride added to the sodium 

 solutions in the proportion of 1 of calcium to 50 of sodium inhibited the 

 shrinkage in sodium at 0.005 M and reduced the shrinkage to half in the 

 0.01 M concentration. In two tests after this series, however, no shrinkage 

 was observed in NaCl 0.01 M. 



Addition of HC1 to NaCl solutions decreased the amount of swelling com- 

 pared to that in the pure salt, and also shrinkage of the tissues took place 

 after the swelling. Addition of KOH did not produce such effects. 



Physical and Chemical Factors in the Growth of Asparagus, by Earl B. Working. 



Asparagus was chosen as a suitable material for a study of certain aspects 

 of the physico-chemical basis of growth. 



Periodic measurements and continuous auxographic records were made 

 of plants grown from storage roots and from seeds. Temperature, light, and 

 soil conditions were varied in the different experiments. 



The hydration capacities of shoots and of seedlings in a large variety of 

 solutions were determined by means of the auxograph. Various chemical 

 analyses and pH determinations were made. 



Two series of sand cultures were grown to get further information concern- 

 ing the effect of various salts, particularly those of Na, Ca, and Mg. 



Commercial practices and conditions were studied, and these observations 

 compared with the experimental results. 



