vi] INFLUENCING THE FORMATION OF ANTHOCYANINS 95 



Fritillaria imperialis was found to produce no colour in sugar solution. 



Ilex Aquifolium. A twig of Ilex was put in 3 % invert sugar. In 

 two days some reddening appeared whereas control plants showed 

 no colour. The pigment was found in the palisade, and to some extent 

 in the spongy parenchyma, but none was present in the epidermis. 

 In glucose and fructose there was also considerable reddening. 



Hedera Helix. In 2-3 % invert sugar, red colour appeared in a 

 few days, but it was not intense nor was it uniformly distributed. 



Mahonia Aquifolium. A twig of this plant gave a negative result 

 in 2 % invert sugar. 



Ligustrum vulgare. In 2 % invert sugar, red pigment appeared 

 after eight days. The pigment was localised in the palisade cells. 



Ampelopsis hederacea. In 2 % invert sugar reddening commenced, 

 but the experiment could not be continued as the leaves tended to fall 

 from the leaf -stalks. In autumn, good results of artificial reddening 

 were obtained, green leaves only, of course, being used. 



Saxifraga crassifolia. In 3 % invert sugar the leaves reddened 

 in a few days. 



Aquilegia vulgaris. Young leaves with petioles in 2 % invert sugar 

 showed distinct reddening in four days. 



Taraxacum ojficinale. When the base of the leaves was placed in 

 a 2 % solution of invert sugar, a very fine red colour developed in two 

 or more days over the whole leaf, and the pigment was located in the 

 inner tissues and not in the epidermis. Leaves, however, in distilled 

 water may redden in time. Reddening of leaves was found to be 

 characteristic of many Compositae, and as this result was often obtained 

 to some extent in distilled water in a good light, they did not afford 

 very suitable material. Leaves of Eupatorium Cannabinum and Pre- 

 nanthes pur p urea which did not redden to any extent in distilled water, 

 became very red in sugar solution. 



Epilobium spp. Leafy stems of E. parviflorum in 2 % invert sugar 

 gave a good red colour. 



Negative results in 2-3 % invert sugar were obtained with 

 Anthriscus silvestris', also with Rubus species. 



From the above researches Overtoil draws the conclusion that in 

 many species of Monocotyledons and Dicotyledons, both water and 

 land plants, sugar-feeding will bring about anthocyanin formation. 

 There is also this further correlation, that, with the exception of sub- 

 merged water plants, there is a negative result with sugar-feeding 

 when the plant in normal circumstances produces anthocyanin in the 



