144 



BOTANICAL GAZETTE 



[FEBRUARY 



Chemical analysis 



Samples were analyzed as in river maple, with slight modifica- 

 tions to suit the material. One-tenth gram of CaC0 3 was added 

 to samples at the time of collection. Figures in the tables represent 

 averages from several samples. Dormant seeds had made no 

 progress in after-ripening. It is almost impossible to choose seeds 

 for the after-ripened samples that are known to be completely 

 after-ripened. The only criterion for completion of after-ripening 

 is germination. The seeds in the after-ripened samples vary 

 from completely after-ripened ones to seeds probably within a 

 week or 10 days of complete after-ripening. 



TABLE VIII 



Sugar calculated as percentage to total dry weight 



Stage 



Free reducing sugar 



Dormant o . 06 



After-ripened 0.67 



Beginning germination, radicles 



about 1 cm 1 ■ 81 



Seedlings with 2-3 cm. radicle 



(with integuments) 1 . 13 



Seedlings with 5-6 cm. radicles! 



(integuments shed) o . 06 



Sucrose 



(as invert sugar) 



6.40 

 4-3 2 



2.36 

 1.80 

 2.62 



Polysaccharides 

 (as glucose) 



5-21 



4.66 

 43 

 9i 

 43 



The protein content of the seeds is exceptionally high. The 

 seeds contain 7 . 1 7 per cent of nitrogen or approximately 44 . 8 per 

 cent protein, calculated on a dry weight basis. The embryo itself 

 contains almost 50 per cent of protein. The nitrogen multiplied 

 by the factor 6.25 was used to indicate the amount of protein 

 present. The seeds contain about 17 per cent of ether extract 

 and 1 1 . 5 per cent of total sugars. The ash percentage is relatively 

 high, 5 .87 per cent of dry weight, while 0.91 per cent of the total 

 dry weight is phosphorus. Only a trace of free reducing sugar is 

 present in the dormant seeds, but sucrose or sucrose-like sugars are 

 present in considerable amounts. Table VIII shows the relative 

 amounts of various sugars at time of dormancy, approximately 

 complete after-ripening, and early stages of germination. 



