CAROTENOIDS IN PLANTS 



that neurosporene (? tetrahydrolycopene, see p. 28), y-carotene, and 

 ^-carotene are also present in small amounts ; phytofluene and 

 phytoene, the colourless partly saturated carotenoids, are also present. 

 A material with an absorption band having a maximum at 256 mjx. 

 occurs in association with phytoene, it remains to be decided whether 

 this is a carotenoid or not. Phytoene has not previously been reported 

 in fungi. 



Differential accumulation of carotenoids has been observed in the 

 sexual forms of some Phycomycetes. Lendner (quoted by Satina and 

 Blakeslee) '^ ^ first noted in 1918 that the ( + ) strain of Mucor hiemalis 

 contained more pigment than the ( — ). This was confirmed by Satina 

 and Blakeslee^i and Chodat and Schopfer^' and extended to Phy- 

 corny ces blakesleeanus by Schopfer. '* Garton et fl/.,^*'2o however, 

 found that their ( — ) strain of Phycotnyces blakesleeanus always contained 

 about twice as much as their (+) strain, irrespective of many variations 

 in cultural conditions. Important results were obtained by Emerson 

 and Fox ^ ^ using various species of the aquatic phycomycete Allomyces. 

 Allomyces spp. can be divided into two types, (a) Euallomyces, which 

 show marked morphological alteration of generations, and (b) Cysto- 

 genes which produce cysts but go through no obvious sexual phase. 

 Two cystogenes were examined, A. cystogena and A. moniliformis ; 

 the former synthesizes no carotenoids whilst the latter produces 

 Y-carotene and distributes it widely and indiscriminately in sporangia, 

 hyphae and spores. The asexual and female plants of the Euallomyces, 

 A. arbuscula, A. javanicus and^. macrogynay synthesize no carotenoids 

 whilst the male forms produce y-carotene and store it specifically in 

 the gametangia in the oil droplets of the cytoplasm, the pigment 

 persisting in the gametes after emergence from the gametangia. Traces 

 of p-carotene also occur alongside y-carotene, but no xanthophylls 

 were ever detected. 



ASCOMYCETES 



As early as 1892 2« Zopf recognized two separate carotenoids in 

 Polystigma rubrum ; this has been confirmed by Lederer, ^ ^ who 

 considers that one is possibly lycoxanthin (see p. 32) ; the second pig- 

 ment in an acidic carotenoid with ill-defined absorption bands having 

 maxima at 516 and 485 mfx. in light petroleum and 550 and 515 m(ji. 

 in CSg. Kohl's 1 very early spectroscopic data on Nectria cinnabarina 

 suggests that it may produce similar pigments. 



Neurospora crassa^ both the wild type and a non-conidiating mutant 

 580, produce a complex mixture of carotenoids most of which are 

 epiphasic. The four major epiphasic pigments were obtained crystalline 



103 



