IQI2] 



DAVIS & ROSE— AFTER-RIPENING 



57 



time to high tempera t 



the cotyledons b 



take 



ripening 



importance of water as a factor in the after-ripening of the 



)hasized. Those seeds kept 



em 



thoroughly wet during this process gave the best results, as indi- 



the germination when removed from the cold. The 



cated 



within the 



shorter period when the carpels were removed, and the still shorter 

 period when both carpels and testas were removed show that these 

 structures add greatly to the resting oeriod. In order tc 



determine 



at the carpels and testas interfered with the taking 

 the embryo, we took two lots of seeds, one with 



soaked in water at room 

 were then removed from i 



rpels removed. Each lot was 



The testas 

 These three 



with carpels intact, one with 

 and testas removed, were dIj 



in Petri dishes and left in an ice chest at about f C. for 14 days. 

 At the end of this period the camels and testas were removed from 



them on. and the 



ent of the embryos determined for t 

 mbryos were dried in vacuo over H 



fere made in dunlirate and arp crivpn i 



4 



three conditions. The 

 The determinations 



TABLE IV 



No. seeds 

 treated 



Condition of 



embryos during 



treatment 



42 



2 9 



44 



44 



3o 



Carpels on 

 Carpels on 

 Testas on . 

 Testas on . 

 Testas off . 

 Testas off . 



Wet weight 



of embryos 



in grams 



O.5114 

 O.3186 

 O.4018 

 O.6056 

 0.6866 

 O.4810 



Dry weight 



of embryos 



in grams 



O.3844 



o. 2396 



0.2730 



0.4180 

 0.4100 

 0.2904 



I 



Water content 

 in grams 



Water content 

 in percentage 



O.127 



O.0796 



0.1278 



O.1876 



O.2766 



O.1906 



24.8 



24.9 

 32.5 

 30.9 



39-4 

 39-6 



Gassner (6) has shown that seeds of two South American 

 grasses, C Moris ciliata and C. distichophylla, after-ripen in dry 

 storage. The most favorable period of dry storage was found to 

 be 30-40 weeks. He also found light to be an important factor 



