On the Specific Gravity of Rice Seeds in Different 

 Stages of Ripening. 



H. Ando, Xd^^akiishi. 



It is a well known fact that the specific gravity of seeds varies 

 in different stage of ripening, but the results obtained by previous 

 investigators do not agree with one another. According to Marek*^'^ 

 and Nowacki/'^^ the sj^ecific gravity of wheat and rye decreases as 

 the seed ripens ; but the result obtained by Lucanus^^^ is opposed to 

 that of those two authors. Such a contradiction is not to be won- 

 dered at when we consider that the sjaecific gravity of seeds varies 

 with various circumstances, e. g. the conditions in which seeds are 

 produced and with different kind and varieties of plants. 



As regards rice seed, which is covered with a light, porous 

 husk, it is exceedingly probable that its specific gravity should \ ary 

 according to different la\\ s from those obtained in other cereals. 

 To get an insight into the matter, I selected, in 1895, some rice 

 seeds at 5 different stages of ripening and determined their specific 

 gravities both in the fresh state and after after-ripening. 



Period I. Milk-ripe : — both grain and straw still green, seeds 

 yielding a white milky juice easily pressed out between fingers. 



Period II. Green-ripe : — husk and straw beginning to become 

 yellowish, endosperm already full, though still very soft. 



Period III. Yellow-ripe : — husk and most straw yellowish ; 

 seed tolerably hard. 



Period IV. Full-ripe : — husk and straw tolerablj' dry and of a 

 pale yellow colour, seed verj- hard. 



Period V. Dead-ripe : — husk and straw entirely dry and of a 

 yellowish white colour. 



(1) and (3) Harz, Samcnkunde, Vol. I. p. 515. 



(2) Xowacki, Getrcidebau, p, 235-239. 



