292 



BOTANICAL GAZETTE 



[OCTOBER 



resistance of the coat to the enlarging embryo, and thereby prevents 

 germination, even in the treated seeds. The facts reported in this 

 paragraph show the danger of applying reagents to intact seeds and 

 drawing conclusions from the results as to the effects the reagents 

 have on the embryos. 



2. Water relations of the embryo and coat. — In con- 



embry 



examine the rate of absorption of water by the seeds under three 

 different conditions: (1) seeds with the coats removed from the 

 micropyle end of the embryo; (2) intact seeds untreated; (3) intact 



seeds 



N HC1 



experiments performed 



TABLE I 



Showing percentage of increase over air-dry weight of Alisma seeds treated as 

 follows: I, 400 seeds in water, coats broken; II, 400 seeds in water, coats intact; 

 III, 400 seeds, coats intact, in 0.2NHCI for 2 hours then transferred to water. 

 Temperature 20 C. 



No. of hours soaked 



I 



2 



3 



4 

 18 



23 



Percentage of increase on basis of air-dry weight 



III 



40 



31.6 



65 



40 



65 



40 



68 



40 



73 



50 



180 



50 



34 



48 



48 

 52 



52 



represent the trend of the results. Table I gives the data for the 



gives the results in the form of curves. 

 Only the general features of the 



in the form 

 xperiment, 



experim 



ment 



value, because of the necessary errors involved in the expen- 

 The seeds are very small, and the 400 used in each culture 

 have a large specific surface. Any variation in degree of drying 

 before weighing gives considerable error. Another variation that 



experiments 

 became effec 



;he promptness with which 

 This accounts for the curve 



.nin 



