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2. Persistence of Germinating Power with Regard to 



Moisture. 



(1) Persistence of the germinating power with relation to the 

 moisture contained in seeds (refer experiment I). 



That the moisture contained in seeds bear a relation to the germinat- 

 ing power is well shown in practice. Everybody knows that wet seeds 

 are liable to fermentation and rottening if kept for sometime. To prevent 

 this, farmers generally expose their freshly gathered seeds in sun light 

 from time to time or dry them by fire. The artificial drying so much 

 advocated by scholars for agricultural seeds was not successful in our 

 investigations on tree seeds. Excessive desiccation of seeds is of course 

 unfavourable to germination ; still the drying at 40° C. for 1 hour as practised 

 in our experiment, can not be regarded as an excessive heat nor as an 

 excessive length of time. 



Haberland who artificially dried seeds at 50°-60°C. for 10 hours to 

 reduce their moisture to half of that air-dried seeds, advocates strongly 

 such a method of desiccation. Our trial in which both temperature and 

 time were far less than those adopted by the German authority showed, 

 however, results telling against artificial drying and led us to the conclu- 

 sion that tree seeds need no drying other than ordinary air-drying and 

 that further treatment is not only useless but harmful. 



• The form of drying commonly followed by farmers of putting tree 

 seeds in the shade so avoiding direct sunshine is indeed the most suitable 

 form of drying. 



(2) Moisture of surroundings of seeds in relation to germinating 

 Power, 



(a) A preservation in a cellar. 



The presence of moisture almost at the saturating point in a cellar 

 exerted an undesirable influence on the germination of seeds as was shown 

 in the second experiment. 



The resistance to excessive humidity is greatest in the case of 

 Hinoki-seeds. Sugi-seeds come next and Akamatsu offers the least resist- 

 ance of moisture, probably on account of the construction of the seed 

 shell which is easily attacked by micro-organisms. 



