147 
THE EFFECT OF AERATION ON PLANTS. 
F. M. AnpreEws, Indiana University. 
A series of experiments on aeration, of which the ones here mentioned 
are a beginning, are being carried out to show what effect will be produced 
on a considerable number of plants of different families and species and 
under different conditions. Some of these have shown, as would be ex- 
pected, a considerable difference as regards their response when placed 
under these conditions. It goes without saying that carefully grown and 
equally vigorous and large controls to begin with should always be used 
and kept under precisely the same conditions except that they are not 
aerated. 
In 1917 Beals! carried out under my direction some experiments on the 
aeration of Zea Mays. In this paper marked differences were shown be- 
tween the aerated and the non-aerated specimens as is well shown by ref- 
erence to his figures. In 1919 a second paper by Andrews and Beals’ gave 
the results of further research on this subject. It became necessary in 
this paper first to ascertain the requisite amount of time for soaking the 
material at hand previous to its germination. The second part of the paper 
deals with the effect of aeration. The experiments on aeration were carried 
out on a more extensive scale than had been done in the above mentioned 
paper by Beals.* This paper not only substantiated the work of Beals but 
extended it in various ways especially as to the different quentities of air 
used and temperature. The photographs show the acceleration produced 
by aeration which was marked in every case. The literature on the sub- 
ject of Aeration of plants is referred to in the paper of Andrews and 
Beals and further reference to it will not be made in these experiments. 
The first plants used in this series of experiments were those of Avena 
sativa. Seedlings of equal size were fastened in the usual way in paraffined 
wooden lids on 1500 ce jars which contained Sachs nutrient solution. From 
the first the aired specimens grew fastest and more nearly normal in every 
respect. Both specimens, however, soon required supports since after at- 
taining some height they were unable to stand upright. To effect this ring 
stands supplied with large rings were used and the upper portions of the 
growing plants: were then passed through the rings. In the control plant 
only two supporting rings were needed but the specimen that had been aired 
had grown to such an extent that three rings, widely separated on the 
ring stand, were required. At the expiration of the experiment the aired 
specimen of Avena sativa was 70 em. high while the unaired plant was 40 
em high. Both plants were then dried and weighed. The dry weight of the 
aired specimen was 3.5 grs. while the dry weight of the unaired plant was 
1 gr. The transpiratory activity of the aired specimen was also much 
greater as would be expected than the aired plant. The root system of the 
aired plant was much greater and more extensive in every respect than that 
1Beals, Colonzo C._ The effect of Aeration on the Roots of Zea Mays. Proc. Indi- 
ana Acad. Sci. 1917, PP. 177-180. 
*Andrews, F. M. and Beals, Colonze C. The effect of Soaking in water and of 
es satel EEG Growth of Zea Mays. Bulletin of the Torrey Bot. Club, 1919, Vol. 
Beals, Colonzo C,, 1, ¢. 
