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TllK KFFKCT OF AFRATlON O.N PLANTS. 



F. .M. .\.M)KK\v,s, Indiana University. 



.\ scries (if cxpcriiiiciits on Mcration, of which the oiics lien- iiioiif iuncd 

 arc a hcuiiniiiii:. arc ticiiii,' carried out to show what elTcct will lie priMluccd 

 oil a ceiisideralilc iimiilicr of plants of different families ami species ami 

 under dilTcrciiI coiHlilions. Some of those have sliown. as would lie ex- 

 pected, a cousidcraiilc difference as regards their response wlien idaccd 

 under these conditions. It };oes without saying tliat ciirefully grown and 

 equally vigcn-ous and large controls to begin witli should always he uscil 

 and kept under iireciscly !li<" same conditions except that they iire not 

 aerateil. 



In lltlT I'.eals' cirricd dut under my direction some experiments on the 

 aeration of Zea .Mays. In this i)aper marljed differences were shown be- 

 tween the aerated and the non-aerated specimens as is well shown by ref- 

 erence to his figures. In l!>l!t a second paper l»y Andrews and Heals- gave 

 the results of further i-esearch on this subject. It became necessary in 

 this paper first to ascertain the requisite amount of time for soaking the 

 material jit hand previous to its germination. The second part of the pajuM- 

 deals with the effect of aeration. The experiments <in aeration were carried 

 out on a more extensive scale than had been done in the above mentioned 

 paper by Reals.-' This i)aper not only substantiated the work of lieals 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 jilauts is referred to in the paper of Andrews and 

 Beals and further refci-eiice 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 e(|ual size were fastened in the usual way in parattiiuMl 

 wooden lids on l."0() cc jars which contained Sachs nutrient soluticm. Fi-om 

 the first the aired specimens grew fastest and more nearly nornml 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 ui)per iM»rtions 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 tlie 

 ring stand, were required. At the expiration of the experiment the aired 

 .specimen of Avena .sativa was 70 cm. high while the unaired ])lanr was 40 

 cm high. Both plants were then dried and weighed. The dry weight of the 

 aired .si^ecimen was :!..", grs. while the dry weight of the uuaire<l plant was 

 1 gr. The transpiratory activity of the aired si)ecimen was also much 

 greater as would be exi.ected than the aired plant. The root system of the 

 aired plant was much .ureater and more extensive in every respect than that 



iBeals, Colonuo C. Tho offfft of Aeration on the Roots of Z.-:. Mavs. I'roc In.li- 

 ana Acad. Sci. 1917. PP. 177-1 so. • 



^Andrews. F. M. and B.-als. Colonze C. The offoot ..f Soakiiifr In wator and of 

 aeration on the Growth of Zea Mays. Bulletin of the Torr.-.v Hot. Club. 191 !t. Vol. 



^Peals, Colonzo C, 1. c. 



