THE SHRINKING AND SWELLING SEED 199 



the seed-coat ratios for the three conditions of the seed, 

 the pre-resting, the resting, and the swollen state pre- 

 paratory for germination ; and in contrasting them we 

 shall be constructing the regime of the shrinking and 

 swelling seed, of the seed as it enters upon the rest- 

 ing period, and of the seed as it subsequently s^yells for 

 germination. 



It has already been established in Chapter II, that the The return 

 seed takes up when swelling for germination the water that fngseedto 

 it lost in the shrinking process, the weight lost during ^ei^f'^*the 

 the shrinking being approximately regained during the pre-resting 

 swelling. But it will be brought out in this chapter that in simple 

 the attainment of this result the parts of the seed take P™"^*^^- 

 different shares, the coverings of the swelling seed never 

 regaining all the water originally lost, whilst the kernel 

 takes up more water than it held in the pre-resting state. 

 However, the loss of the one tends to counterbalance the 

 gain of the other in the following fashion. The deficiency 

 of the coats is generally larger than the excess of the 

 kernel ; but since the coats as a rule are only one-half 

 or one-third of the weight of the kernel, the ultimate 

 result is usually not much affected. Nevertheless, this is 

 sufficient to show that the return of the resting seed 

 when swelling for germination to its original weight as a 

 pre-resting seed is not a simple process, and that such a 

 result of experiments can only be regarded as approximate 

 in value. 



In the following table are given the data for construct- Theelements 



ing the regime of the shrinking and swelling seed in a w the*^""" 



considerable number of cases. Knowing the weight of- shrinking 



.... J „. . ° , , and swelling 



the restmg seed, the shrmkmg and sweilmg ratio, and the regime. 



proportional weight of the coverings (the seed-coat ratio) 



in the three conditions of the seed, the determination of 



the shrinking and swelling regime for any seed named in 



the table can be readily effected, as shown in the example 



added. 



