ig2o\ JONES— MAPLE SEEDS 133 



filter paper was packed very loosely in the graduated cylinder. The 

 seeds were washed with distilled water and planted near the surface 

 of the paper, about midway between the top and bottom of the 

 chamber. A small amount of water was run into the respirometer. 

 The top was stoppered and supplied with an inlet tube which 

 extended to the bottom of the chamber and brought in the carbon 

 dioxide free air, and with an exit tube which carried the carbon 

 dioxide laden air to the Reiset tube. The seedlings were grown 

 in the dark and consequently there was no food manufactured. 

 Storage food only was used up in respiration. 



The respiratory activity of the germinating seeds reaches a 

 maximum about the eighth day at this temperature. At this time 

 the seedling has elongated considerably, the radicle having attained 

 a length of 7-10 cm., varying considerably with the individual. 

 After the eighth day respiration decreases gradually. Seeds 

 stored for several weeks at a low temperature (o° C.) and then 

 transferred to a high temperature (25 C.) in germinative conditions 

 show a very high initial respiratory intensity, which soon drops 

 to normal, and then again increases. Palladin (20) found that 

 transferring the tips of etiolated bean seedlings from a lower to a 

 higher and also from a higher to a lower temperature increased the 

 respiratory activity. According to Applemax (i), tubers stored 

 at low temperature for several weeks and then transferred to room 

 temperature respire more intensely than tubers of the same lot 

 not subjected to the cold storage conditions. He thinks thi 

 increased respiration might result from the increased accumulation 

 of sugar at the lower temperatures. 



Fig. 2 shows the march of respiration during the first 14 days 

 of germination in the dark. In general this curve agrees with that 

 found by Rischawi (21) for the respiration of the wheat seedling 

 growing in the dark, but is quite different from that found for 

 the bean. 



■ 



Catalase activity 



The apparatus used for catalase determinations was a modified 

 lorm of the one used by Appleman (2) . Determinations were made 

 upon fresh seeds, seeds desiccating at 25° C, and also seeds germi- 

 nating in the dark at 25 C. Entire seeds were used in all cases. 



