Apr. i, 1921 
Growth and Sap Concentration 
83 
numbered tag and was marked near the base with a line of India ink. 
The distance from the basal ink mark to the tip of the shoot was easily 
determined and recorded for each shoot. 
GROWTH INCREMENTS AND SAP CONCENTRATION OF YOUNG WAENUT 
TREES 
Determinations on the concentration of the cell sap of young walnut 
trees (Juglans spp.) were made at frequent intervals and compared 
with the increments in mean height of similar trees growing in the 
same rows. The measurements given in Table I were made upon a 
population of J. regia trees, of which the majority were propagated 
upon J. nigra rootstocks and the remainder on a variety of J. regia 
known as “Hardshell.” The trees from which the material for inves¬ 
tigation was taken were in their second season’s growth. They stood 
in the nursery row in a fertile soil and were artificially irrigated. The 
first samples for determinations were taken June 8 and the last on 
November 12. 
The growth rate of a portion of this group of walnut trees has been 
discussed in a recent publication ( 12) and has been shown to follow the 
course of autocatalytic reactions. 
Table I .—Mean growth increments and concentration of cell sap of walnut trees 
Date. 
Mean 
height. 
Increment 
of growth 
during 
preceding 
week. 
Osmotic 
pressure of 
cell sap. 
June 12 
Cm. 
62.6 
Cm. 
12. 6 
A tmospheres. 
16. 5 
*9 
66.6 
4-0 
13 • 5 
26 
73 - 7 
7 - 1 
18. 4 
July 4 
87. 2 
* 3-5 
9 - 7 
II 
100 8 
13. 6 
11. 4 
23 
125-9 
6 IS- 0 
10. 4 
A 30 
136. 7 
10. 8 
10. 8 
Aug. 6 
147. 6 
10. 9 
13 
153.4 
5-8 
17.8 
20 
0 160. 9 
a 7 - 5 
0 27 
168. 4 
0 7 - 5 
12. 5 
Sept. 4 
176.7 
8.3 
9. 2 
10 
184. 2 
& 8. 7 
8.9 
17 
188. 1 
3-9 
10. 2 
24 
I 9 I * 3 
3-2 
18.8 
Oct. 1 
194. 6 
3-3 
n. 7 
8 
196. 8 
2. 2 
20. 9 
*5 
199.0 
2. 2 
13.2 
22 
igg. 7 
0. 7 
17. 1 
XT 29 
201. 2 
5 
13- 5 
Nov. 5 
201. 2 
0. 0 
24.4 
1 
° Interpolated values. b Calculated to 7-day basis. 
29668°—21-7 
