

r 



318 



BOTANICAL GAZETTE 



[OCTOBER 



soils. The amounts of water that froze at different temperatures are 



reported in table I. 



TABLE I 



Amount of water freezing in leaves of plants at different temperatures 



/~1 



Date 



Weight of 



material 



(gm.) 



Freezing 



point 

 lowering 



Cc. water that froze 



Crop 



-i.5°C. 



-4 C C. 



-6°C. 



Rye 



Rye 



Wheat 



Nov. 24 

 May 17 

 Nov. 24 

 Nov. 24 

 May 15 

 June 10 



5 

 5 

 5 

 5 



5 



5 



O.928 

 I.030 

 1. 107 

 O.906 

 O.780 



0.578 



O.90 



; 0.86 

 0.40 

 1.22 

 1.70 

 2. 10 



2.50 

 2.4O 

 2.65 



2.86 

 2.70 

 2.40 





2.90 



Swppt clovpr 





Red clover. . . 

 Corn 



2.90 







Marked variations in the amount of water that froze at 



i.S°C 



2-5 



and 



4 



°c. 



were observed, and while the amount increased with the lower tempera- 

 tures, less differences were recorded. 



The effect of the concentration of the soil solution and the water 

 content of the soil were determined. The density of the solution in the 

 soil was increased and so maintained by additions of the three salt 

 solutions of Shive and the soil placed in 3 gallon jars and plants grown 

 therein. The containers were placed in the open and exposed except 

 when it rained. 



Marked increase in the density of the soil solution resulted in little 

 if any effect on the amount of water that froze at 

 respectively. The results are not given, inasmuch as Millar is to 

 report them in another article. 



The amount of water in the soil affected the quantity of water that 

 froze in the plants grown therein. Corn was grown 60 days in sandy 

 loam soil containing 9 . 5 and 15.6 per cent water respectively; 44 . 1 per 

 cent of the loss in weight of the corn upon drying, froze at — 2 . 5 C, and 

 63.9 per cent at — 4 C. in the former and 51.8 and 84.8 per cent 

 respectively in the latter. Similar results were obtained with barley. 



In another series the moisture content of the soil was varied, but 

 the concentration of the soil solution was kept about the same throughout 

 the experiment by additions of the nutrient solution. In case of the 

 higher temperature the results obtained were the reverse of those just 

 given, or the amount of water that froze in the eorn plant increased 

 with a decrease in the water content of the soil when the nutrients were 

 added. Slight differences were observed when the tissue was exposed 



to a temperature of — 4.5 C. 



