The Oxydases of Cytisus Adami. 



4G1 



cells bear yellow flowers of the laburnum type. The purple flowered 

 branches arise exclusively from epidermal cells, and are, therefore, similar 

 to those of C. purpureas. 



The investigations, the results of which are now to be described, were 

 undertaken with two objects. In the first place, they were designed to test 

 the validity of Baur's hypothesis, and, in the second place, to determine 

 whether the results of an examination of the distribution of oxydases in 

 C. Adami and its component species would confirm the hypothesis, to which 

 our previous work (Keeble and Armstrong, 1912) has led us, that oxydases 

 may migrate from one part of a plant to another. 



We may say at once that the results of our investigation of the distribution 

 of oxydases in C. Adami serve to confirm the general truth of Baur's 

 conclusions and to support the thesis that oxydases may migrate from cell 

 to cell. 



The methods which we employ for determining the distribution of oxydases 

 in plant-tissues are described in our former contribution. 



The results obtained by the use of benzidine are as follow : Petals of 

 G. purpureus treated with an alcoholic solution of benzidine and incubated at 

 37° C. for half an hour are first decolorised and then give a direct oxydase 

 reaction, that is one which declares itself without the addition of hydrogen 

 peroxide. The reagent produces a grey to bluish- brown coloration of the 

 general surface of the petals, more marked in the marginal region, and a 

 similar but deeper coloration of the veins. In other words, C. purpureus 

 contains an epidermal oxydase and also a bundle oxydase. 



The petals of the purple (magenta) flowered branches of C. Adami — which 

 branches are, on Baur's hypothesis, pure C. purpureus — give similar, albeit 

 somewhat fainter, reactions, thus indicating that the oxydases of the purple 

 branches of G. Adami are identical in kind and distribution with those of 

 G. purpureus. When treated with benzidine the typical buff-coloured flowers 

 of G. Adami do not become completely decolorised. This is owing to the 

 fact that they contain, in addition to an anthocyanic epidermal pigment, 

 a yellow pigment of the carotin type, which lies, in both C. Adami and 

 C. laburnum, in the sub-epidermal cells. Nevertheless, despite the fact that 

 the carotin pigment is present, it is easy to determine, either by direct 

 inspection or by microscopic examination of surface sections of the petals, 

 that the buff-coloured flowers of C. Adami contain epidermal oxydase. 

 In this respect G. Adami differs from the yellow G. laburnum and from the 

 laburnum-like flowers of the yellow-flowered branches of G. Adami, neither 

 of which contains epidermal oxydase. We conclude, therefore, that the 

 epidermis of C. purpureus contains an oxydase, that this oxydase is present 



