I9I2] 'Alfred P. Lothrop 183 



38. The comparative enzyme content of green and varie- 

 gated leaves of Tradescantia.^^ Carl A. Schwarze. The re- 

 sults of the experiments made to determine the relative enzyme con- 

 tent of green and variegated leaves of Tradescantia show that there 

 is a marked difference between Juices expressed from them. Etio- 

 lated leaves are yellow in their rudimentary stage ; that is, an entirely 

 yellow leaf presents this condition when first formed. The etio- 

 lated leaves are free from chloroplasts and therefore possess no 

 starch. The juice extracted from yellow leaves gives a negative 

 Fehling test; that from green portions, a positive test. When yel- 

 low leaves are ground in a mortar, and the juice is expressed 

 through cheese cloth, a dark brown liquid results. Green leaves 

 similarly treated yield a dark green liquid. Alcoholic extracts of 

 crushed green and yellow leaves, when filtered, assume a brown 

 color. The filtrate from yellow leaves is at first pink but the liquid 

 gradually assumes a brown color. The filtrate from the green 

 leaves comes through brown immediately. The juice of yellow and 

 green leaves, when filtered, gives in both cases a brown filtrate, that 

 from the yellow leaves being a reddish brown, When unfiltered 

 green juice desiccates, a glossy dark green residue is deposited, 

 at the periphery of which a few needle-shaped crystals are seen. 

 The juice from the yellow leaves, upon desiccation, deposits a 

 brown crystallin mass, the long crystals of which make a figure 

 which resembles a polyaster seen in plant cells. Extracts in alcohol 

 (80 per Cent.) deposit the greatest amount of crystals. The crys- 

 tals from yellow leaves are darker than those from green leaves. 



Such reagents as guaiac and trikresol show the presence of 

 oxidase and peroxidase in yellow and green Juices. The yellow 

 juice seems to be richer in oxidase and peroxidase. When green 

 juice was heated to 72° C, and tested the following day, oxidase 

 proved to be present, that temperature having failed to destroy it. 

 (Subjecting green juice to high temperatures results in the produc- 

 tion of a flocculent precipitate, which Sediments promptly under a 

 clear supernatant liquid.) 



Juice from yellow leaves was injected into the nodes and inter- 



** Conducted in the Botanical Laboratory under Dr. Gies' guidance. 



