44 



STUDIES IN SEEDS AND FRUITS 



(6) by imper- 

 meable seeds. 



gators, have all been converted into percentages of the weight 

 of the resting seed carrying its normal water-contents. 



COMPARISON OF THE MINIMUM AMOUNT OF WATER REQUISITE FOR 

 GERMINATION, AND OF THE AVERAGE QUANTITY ABSORBED UNDER 

 NATURAL GERMINATING CONDITIONS, WITH THE MAXIMUM AMOUNT 

 THAT A SEED CAN TAKE UP, i.e. THE AMOUNT NEEDED FOR 

 SATURATION. (Stated as percentages of the weight of the normal 

 resting seed.) 



G=Guppy. H = Hoffmann. J=Jodin. N = Nobbe. T = Van Tieghem. 



I have endeavoured here to give the general run of the 

 results. The critical results are of course those made by the 

 same investigator on the same set of seeds. Thus we notice 

 particularly in the case of " Feves " (assumed above to be Faba 

 vulgaris} Van Tieghem's estimate of 74 per cent, as the 

 minimum amount of water required for germination and 1 1 8 

 per cent, as the maximum amount that a seed can absorb. So 

 again my own results for Faba vulgaris (Broad Beans) were 

 very definite, 95 per cent, being the average for germination 

 and 1 20 per cent, the amount needed for saturation. The 

 general indications above afforded for seeds of the types of 

 the Pea (Pisum} and the Bean (Faba) clearly show that whilst 

 the minimum amount of water required for germination is 

 about 70 per cent, of the weight of the resting seed, a con- 

 siderably larger quantity of water is needed for saturation, viz. 

 no to 1 20 per cent. Between these two extremes lie the 

 average amounts of water required for germination under 

 ordinary conditions, as determined from the observations of 

 Hoffmann, Nobbe, and myself. 



The seeds of Pisum sativum and Faba vulgaris are typical 

 permeable seeds. Similar indications were presented in many 

 of my experiments on impermeable seeds of the same family. 



