March, 1922. 



SCIENTII-IC AGRICULTURE 



229 





o 



Q 



8% 



o% 



r,o5 



Time in Datjs 



Germination of Poo comprQ^^a CL ) 



[If feel's of steady and fluduating tamperofure conditions 



The tabulated results iu Table II show 

 the effects of these different temperature 

 changes, but these effects are more readily 

 appreciated from an examination of the 

 curves in Figure 5. In this figure the 

 abscissa represents time, and the ordinate 

 percentage germination. 



The nine lowest curves represent the re- 

 sults obtained at steady temperatures and 

 where fluctuations of five degree C. oc- 

 curred. In none of these cases did tlie 

 germination percentage rise to 18. The 

 next thiee higher curves show results ob- 

 tained Avitli ten degrees C. fluctuations, 

 the percentage ranging between 22 and 36. 

 Next higher are two curves, representing 

 results where the fluctuation was 15 de- 



grees C, the percentages ranging between 

 49 and 53. The highest curve showing a 

 germination of 54.3 per cent, illustrates 

 the effect of a fluctuation of approxim- 

 ately 20 degrees. 



These curves present clearly the conclu- 

 sion that may be drawn from this experi- 

 ment, viz., the greater the extent of the 

 fluctuation of temperature between 16 de- 

 grees C. and 35 degrees C, the higher the 

 germination percentage. It may be that 

 a greater fluctuation would give higher 

 results, but tests have yet to be made to 

 determine this point. These percentages, 

 even the highest of them, may seem low, 

 but it must be remembered that the tests 



