PLANTS IN GLYCOCOLL SOLUTIONS 
183 
The numerical relation between the quantity of water retained and 
the amount of growth, i. e., the difiference between the initial and final 
green or dry weight of the plant, may well be termed the coefficient 
of growth. This value may serve as a criterion for problems in 
dynamic ecology and in agriculture. 
10. The retention of water is the physiological function correlated 
with and indispensable to growth in general, and to survival and 
greater areal distribution of the plants entering physically or physio- 
logically arid habitats. 
Table VIII. 
Transpiration and Growth of Coleus sp. in HCl Solutions 
November 23 to December 2, 1913 
Culture solution 
Amount of water in grams 
Gain or loss in weight 
of plants (in grams) 
Absorbed 
Transpired 
Retained 
I. 
4.18 
3.95 
0.23 
0.23 
2. 
6.55 
6.15 
0.40 
0.40 
3. 
w/800 HCl 
29.65 
29.10 
0.55 
0.55 
4- 
nil, 600 HCl 
14-15 
13-50 
0.65 
0.65 
5- 
w/3,200 HCl 
5-85 
5-55 
0.30 
0.30 
6. 
w/i2,8oo HCl 
4-15 
3-85 
0.30 
0.30 
Color of leaves dark green in bog water, lessening in intensity as solutions de- 
crease in concentration. Immersed portion of stem curved in stronger acid solutions 
and without roots; more or less gelatinized and brown. Roots and roothairs in 
weaker solutions; with brownish tips. Atmometer, 76.5 cc. Temperature, 8°- 
28° C. Relative humidity, 40%-g8%. Barometer, 29.4-29.9 cm. 
Table IX 
Transpiration and Growth of Wheat Seedlings (Triticum vulgare) in 
Glycocoll Solutions 
October 28 to November 5, 1913 
Culture solution in duplicate series 
Transpiration 
in grams 
Green weight 
of plants 
Dry weight 
of plants 
I. 
81.67 
5-030 
0.485 
2. 
62.40 
4-935 
0.580 
3. 
60.05 
4.480 
0.515 
4. 
73.10 
4.980 
0.535 
5- 
82.75 
5-415 
0.515 
6. 
w/i2,8oo glycocoll ! 
85.10 
6.655 
0.535 
Atmometer, 143 cc. Temperature, i5°-37° C. Relative humidity, 40%-83%. 
