1909.] 



Latent Life of Resting Seeds. 



421 



presence of a more or less considerable quantity of a diastase ferment in the 

 precipitate obtained from the extract of the crushed resting seeds. This 

 ferment was present as such, and not as a zymogen in the resting seed, and 

 was destroyed by boiling, as shown by the experiments performed with the 

 test-tubes C. 



The experiments were performed as far as possible in pairs, in one of which 

 freshly harvested grain, and in the other old grain of the same kind, whose 

 germinating power was lost, were tested. 



It was impossible to carry out any additional control experiments with the 

 aid of commercial diastase, for this was found in all cases to contain reducing 

 sugar, and it was not found possible with the means at hand to prepare 

 sufficient quantities of pure diastase from the material available. 



It has been stated that the artificial addition of commercial diastase to 

 ungerminable or feebly germinable seeds may bring about or increase their 

 germination,* and the idea that ferments are connected with the vitality of 

 seeds is a fairly prevalent one.f 



In order to test this statement, samples of such seeds were sown on damp 

 blotting paper, and a little dissolved commercial diastase was added to them. 

 Similar numbers from the same packets of seeds were sown on damp blotting 

 paper and, instead of dissolved diastase, a little plain water was poured over 

 them. In addition, two similar sets of seeds were sown as above, but the 

 seed coat of each seed, both in those treated with dissolved diastase and with 

 water alone, was pierced once with a needle. In this way the entry of the 

 ferment was assured even in the presence of a more or less impermeable 

 integument. 



Not all the seeds which were tested for the presence of diastase were thus 

 treated, chiefly owing to the limited quantity of the available material, but 

 sufficient experiments were performed with each kind of seed to ensure 

 accuracy of results. 



Effect of Addition of Diastase. — The addition of the dissolved diastase to 

 intact seeds does not materially affect their germinating power, and in no 

 case does it bring about germination in otherwise non-germinable seeds. The 

 presence of external diastase aids the development of bacteria and interferes 

 with the aeration of the seeds, which may be sufficient in some cases to 



* Thompson, ' Garten- Flora,' vol. 45, p. 344, 1896; Waugh, 'Ann. Rept. Vermont 

 Agric. Exp. St.,' 1896—7; 'Science,' N.S., vol. 6, p. 950, 1897; Sharpe, 'Mass. Hatch 

 Exp. St.,' 1901, p. 74. 



t Brnyning, Jr., F. F., " Relation entre le pouvoir germinative et l'aetivite diastatique 

 de graines non-germees" ; Albo, G., 'Bull, della Soc. Bot. Ital./ 1908 ; ' Archiv des Sci. 

 phys. et nat.,' vol. 25, p. 45. 



VOL. LXXXI. — B. 2 I 



