July 7,1923 
Temperature Effects in Plant Metabolism 
21 
on the rotating tables. Each table bore six culture jars, a thermograph, 
a hygrograph, one white atmometer and one black one. The period of 
rotation was 40 seconds. 
The seedlings appeared and were uncovered in 3 days at the higher 
temperature and one-half day later at the lower one. Thereafter the- 
soils were brought to equal moisture content by weighing daily. On 
March 3 the number of plants per jar was reduced to 3 at the higher 
temperature, and a similar reduction was made at the lower temperature 
on March 5. On the latter date the plane of soil moisture was increased 
to 40 per cent of saturation. It was further increased to 50 per cent on 
March 19, and later reduced by two equal steps, on April 14 and 26, to 
30 per cent. In the course of development aerial roots and red pig¬ 
mentation appeared freely on the base of the stems for some distance 
T/me (OE?yis) 
Fig. i.—R elative evaporation (black atmometers) and relative solar radiation (ratio of evaporation 
between black and white atmometers). Climatic chambers, 1920. 
above the soil. These features were especially prominent at the higher 
temperature. 
On March 27, buds were unfolding at the higher temperature, although 
they were just appearing at the lower one. Several seeds had turned 
brown at the higher temperature on April 27, while those of the other 
cultures were still green. Photographs were taken on April 30. On 
May 10, the plants were harvested and separated into parts, as follows: 
leaf blades, petioles and stems, and seeds. These were dried at ioo° C, 
and ground fine for chemical analysis. The data of climatic measure¬ 
ments and plant composition appear in Tables IV and V, while Plate 
2, A, shows the appearance of the plants. Plate 3 shows the thermo¬ 
graph and hygrograph records. These are given for one week only, 
as it is hardly feasible to reproduce them in full. The graphs of figure 1 
are constructed from the atmometric data. 
