252 U. SUZUKI ; ON AX nirORTANT FUNCTION OF LEAVES. 



parts of the plants by the assimilation of nitrates, yielding there- 

 by amido-coin pounds, which are in all probability better sources 

 for proteid formation than nitrates, in organs poorer in sugar and 

 with a less energetic respiration process. A great advantage 

 is thus gained for the stems, roots and fruits, in which the condi- 

 tions for nitrate assimilation are less favourable than in the leaves.''^ 

 These amido-compounds produced are either asparagine, which, 

 as I have shown in former article, can be formed synthetically from 

 ammonium salts as well as from nitrates, or they are the de- 

 composition products of proteids formed in the assimilation of 

 nitrates. This leaf function will play an important part especial- 

 ly in plants of rapid growth (as many Leguminosae) or such plants 

 as develope certain parts much more than others (as the turnij:), 

 melon, potato).^^' 



Addenduui. 



After this investigation was finished, a recent publication of 

 P. Kosutany^^^ came to my knowledge, which also treats of the 

 proteid formation in leaves. But I think that his observations 

 cannot be regarded as conclusive in regard to those functions of 

 leaves I have had under discussion. He collected the leaves 

 between three and four o'clock in the afternoon and then again at 

 three o'clock in the morning. Thus the leaves would not show 

 differences as large as in my investigations, since I collected 

 the leaves at six o'clock in the morning and six o'clock in the 

 evening, which in September and October means in the latitude 

 of Tokyo nearly twelve hours of daylight and twelve hours of 

 darkness. 



(1) Cf. Nakamura's contribution, this Bulletin \o\. III. No. 7. 



(2) In cases however of slow development, the proteids formed in the cells of the 

 leaves may remain there stored up for a long time, as active albumin. Cf. Daiktihara, 

 this Bulletin II. No. 2 and 4. 



(3) Land\v. Vcrs-Stat. ^6". 13. 



