CAROTENOIDS IN PLANTS 



It is obvious, as Bonner et al. fully appreciated, that is only one of a 

 number of possible interpretations of their results. 



After 2\ years of monthly transfers of these mutants on agar, their 

 phytofluene content had markedly diminished whilst that of the other 

 carotenoids had not altered. * ^ 



Table 18 



Quantitative distribution of Carotenoids in various ultra-violet mutants of 

 Torula rubra (from Bonner, J., Sandoval, A., Tang, Y. W., and 

 Zechmeister, L. (1946) Arch. Biochem., 10, 113) 



Function 



{a) In photokinetic responses. Most work which has been carried out 

 on the function of carotenoids in fungi points to their taking part in 

 photokinetic responses. ' * 



As in the case of the oat seedling {see p. ^) Blaauw ' ^ made the 

 pioneer measurements of the action spectrum of phototropic bending of 

 a fungus, Phycomyces nitens. Later, Castle ^* found that action spectrum 

 of P. blakesleeanus had a maximum at about 440 m(jL., and this has been 

 confirmed."*'" By measuring photoelectrically the difference in 

 light absorption between pigmented and colourless zones, Biinning'^ 

 obtained an absorption curve very similar to the action spectrum, with 



117 



