Some new considerations in the biogenesis of sap-soluble pigments
The sap-soluble pigments of plants consist of anthocyanins and a number of related groups of anthoxanthins. Any comprehensive theory of biogenesis should embrace all these groups. The theories of sequential and parallel origin are discussed. Based on chemical considerations with reference to certain methyl ethers and glycosides of anthoxanthins it is concluded that sequential origin should be recognised as playing a definite part though parallel evolution may be the major factor. Further, glycoside and ether formation may not be the last stages in evolution in all cases.