ASSIMILATION AND METASTASIS. yxg 



Asparagin is first found in the hypocotyledonary portion and root when they are about 

 lo mm, long, but then rapidly increases in quantity while these parts elongate ; and it is 

 now found also in the petiole of the cotyledons, and in the cotyledons themselves before 

 they have become green and thrown off their testa, especially in their lower part. The 

 conditions remain the same during the whole of the time that the reserve albuminous 

 substances are being consumed. Asparagin is now found in large quantities in the petiole 

 of the cotyledons, almost to the extent of a saturated solution (i part dissolves in 58 parts 

 of water at 13° C), as well as in the hypocotyledonary portion and in the stem as soon as 

 it begins to grow. The asparagin extends in the root and stem towards the puncta 

 'vegetationis almost exactly as far as the sugar, becoming finally, like the latter, less 

 abundant. Beneath the cotyledons it is wanting in the pith, while in the stem it is as 

 abundant there as in the cortical tissue ; it is never found in the vascular bundles. The 

 asparagin also extends into the petiole of young leaves as far as the base of the unfolding 

 pinnae, as well as into the lateral roots. As long as asparagin is formed out of the albu- 

 minous substances in the cotyledons, it may also be found in the plant distributed as has 

 been described ; but when the cotyledons have been entirely emptied, the asparagin also 

 disappears ; but this does not happen in the case of Lupinus luteus until several leaves have 

 completely unfolded. 



The process is quite analogous in letragonobolus purpureus and Medicago tuber- 

 culata ; in Ficia sati'va and Pisum sati'vum the presence of asparagin in the cotyledons 

 themselves cannot be proved with certainty, but is found at their base and usually also 

 in their petiole, although these plants produce decidedly less of it than Lupinus luteus. 

 Since moreover chemical analysis has established the production of great quantities of 

 asparagin on germination in the case of a large number of other species of the order, we 

 may regard this substance as the form of transport for the albuminous substances 

 characteristic of all Papilionaceae. Albuminous substances are moreover found in 

 these plants also in the thin-walled elongated cells of the vascular bundles; and it is 

 quite possible that they are at the same time also transported by these structures. It is 

 evident that the source of the asparagin must be the albuminous substances, because the 

 absolute amount of nitrogen remains the same during germination ; and the nitrogen of 

 seeds is all or nearly all contained in their albuminous ingredients. 



The following numbers show the percentage composition of asparagin, and the 

 composition of an amount of legumin, containing an equivalent quantity of nitrogen. 



Asparagin contains less Carbon and Hydrogen but more Oxygen than Legumin and 

 other proteids. Consequently if the whole of the Nitrogen of Legumin is used in the 

 formation of asparagin, a considerable quantity of Carbon and Hydrogen must be given 

 off and a certain amount of Oxygen absorbed. Exactly the opposite will take place upon 

 the conversion of asparagin into proteid. Pfeffer points out (Monatsber. d. Berl. Akad., 

 1873) that this regeneration of proteid from the asparagin formed during germination 

 depends in so far upon the action of light as this is necessary for the decomposition of 

 carbonic acid in cells containing chlorophyll. Asparagin remains in a plant exposed to 

 light if carbonic acid be not supplied to it. 



In TropfEolum majus asparagin occurs in the earliest stages of germination only; it 

 disappears at a later period whether germination is taking place in light or in darkness. 

 In this case the asparagin is converted into proteid before the non-nitrogenous reserve- 

 materials are exhausted; hence the regeneration can take place without assimilation. 

 The formation of asparagin during germination takes place in light or in darkness : it is 



