'■ — Zea 

 Zeaxanthin 



X 



I- 



X 



I 



-m 



■n 



Isorhamnetin 

 (Gynotermone I ) 



Peonin 

 (Androtermone II ) 



Precursor 



Protocrocetin ? 



Crocetin 



Cro- 



Picrocrocin 



-MD 



Crocin 



Fd 



Gynotermone 



n 



Quercetin 



ru 



Gat he- CIS — 

 Gathe-trans- 



4-oxy-B- 



cyclocitral 



(Androtermone I ) 



cis/trans 

 Crocetin dimethyl 

 esters (Gamones) 



X 

 Rutin 

 (gamone 

 inhibitor) 



Rutinose 

 runo \^ \ 



Rhamnose 

 A 



Glucose 



rha- 



evidence, however, that other allied species each possess a species- 

 specific glycoside of crocetin. The gene mot is responsible for split- 

 ting the picrocrocin-crocetin precursor, and two genes, gathe-cis 

 and gathe-trans, determine the proportions of cis- and trans-cro- 

 cetin dimethyl ester. Since gathe-cis is said to be activated by 

 visible light of all wave lengths and gathe-trans only by blue or 

 purple light, it is somewhat difficult to see how the apparently 

 exact ratios of cis-/trans- in the different gametes are produced and 

 maintained. The presence of rutin, a gamone inhibitor is also of 

 great interest, but it is of importance to note that the chemistry of 

 rutin and isorhamnetin in relation to this alga has recendy been 

 repeated at the University of Sydney. This is significant because all 

 the previous biological and genetical work comes from a single in- 

 vestigator, whilst the biochemical work also was performed at one 

 place only. Many workers have therefore felt that the novelty of the 

 results demands repetition. In other Chlorophyceae, including 

 species of Chlamydomonas, gametes are Uberated and function even 

 when thalli are in the dark. Any sex hormones in these cases, there- 

 fore, cannot be carotinoids formed in light. 



420 



