EFFECTS UPON GERMINATION 



807 



of E. angustifolium gave some germination in darkness and good germina- 

 tion in light, while seeds stored dry for 6 months germinated equally well 

 in light and dark. According to Lehmann (63), properly after-ripened 

 E. hirsutum germinated well in darkness at 20° to 25°C. In Axentieff's 

 (3) experiments seeds of E. hirsutum at 14° to 18.5°C. germinated equally 

 well in light and darkness if the coats were pricked with a pin to admit 

 sufficient oxygen. Pricking the coats improved germination even in 

 light. According to Bihlmeier (7) soaking E. hirsutum seeds more than 

 8 hr. reduced their light sensitiveness, but this effect was overcome by 

 increasing the period of illumination. 



Both Lehmann (61) and Gassner (24) found that high constant 

 temperatures favored the germination of E. hirsutum in darkness. 

 Fassbender (16), on the other hand, claimed that high constant tem- 

 peratures had no favoring action in darkness and he found intermittent 

 temperatures effective in displacing the need for light. Gassner showed 

 daily intermittent temperatures to be more favorable than the best 

 constant temperature, especially if the low temperature was used for the 

 long period. Gassner's results with Epilohium are given in Table 6. 



Table 6 



As is evident from Table 6, daily intermittent temperatures proved 

 highly effective as a substitute for light. 



In Fassbender's (16) work dilute HCl had little, if any, effect on seeds 

 of E. hirsutum unless combined with daily intermittent temperatures or 

 short exposures to light. Hesse (41) showed that dilute HCl and H2SO4 

 at 22°C. in darkness did not increase the germination of seeds of E. 

 angustifolium, E. roseum, E. hirsutum, or E. montanum, but that dilute 

 HNO3 and other nitrogen compounds favored germination of these seeds 

 under the same conditions. Gassner (25) had previously found N com- 



