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In flowers of Matthiola incana, the B-ring hydroxylation pattern of anthocyanins is controlled by the locus b. Recessive genotypes produce pelargonidin and genotypes with wild-type alleles cyanidin as the aglycone. Supplementation experiments on acyanic flowers using extracts of pelargonidin-and cyanidin-producing flowers, respectively, showed not only the presence of compounds with a precursor function for anthocyanin synthesis in the cyanic flowers but also differences in the B-ring hydroxylation pattern of these compounds. Chromatographic investigations proved that flavanones and dihydroflavonols occur in extracts of cyanic flowers. Naringenin, dihydrokaempferol, and their 7-glucosides could be demonstrated in all flower extracts, but in extracts of cyanidin-producing flowers, dihydroquercetin and a further 3′, 4′-hydroxylated dihydroflavonol, tentatively identified as dihydroquercetin 3-glycoside, were additionally found. In no case, however, could eriodictyol be detected. From these results and from the ready hydroxylation of dihydrokaempferol to dihydroquercetin in a white mutant line of Matthiola incana, it can be concluded that introduction of the 3′-hydroxyl group of anthocyanins is not achieved by specific incorporation of caffeic acid during synthesis of the flavonoid skeleton, but by hydroxylation at the dihydroflavonol stage.

To study the fate of homologous DNA in a recipient system a specific labelling procedure is necessary. We use a 3H-adenine/ BrdU labelled donor DNA from Matthiola seedlings (buoyant density: 1.741 g/cm3) and intact seedlings grown in water as recipient plants (DNA buoyant density: 1.698 g/cm3)

In flower extracts of defined genotypes of Matthiola incana, an enzyme was demonstrated which catalyzes the transfer of the glucosyl moiety of uridine 5'-diphosphoglucose (UDPGlc) to the 5-hydroxyl group of pelargonidin and cyanidin 3-glycosides and acylated derivatives. The best substrate for 5-glucosylation is the 3-xylosylglucoside acylated with p-coumarate, followed by the 3-xylosylglucoside and by the acylated (p-coumarate) 3-glucoside. The 3-glucoside itself is a very poor substrate. Besides UDPGlc, thymine 5'-diphosphoglucose is a suitable glucosyl-donor, but with a reduced reaction rate (42%). The anthocyanin 5-O-glucosyltransferase exhibits a pH optimum at 7.5 and is generally inhibited by divalent ions and by ethylenediaminetetraacetic acid and p-chloromercuribenzoate. Investigations on different genotypes showed that the 5-O-glucosyltransferase activity is clearly controlled by the gene l. In confirmation of earlier chemogenetic work, enzyme activity is only present in lines with the wild-type allele l(+). The anthocyanin 5-O-glucosyltransferase activity is strictly correlated with the formation of 5-glucosylated anthocyanins during bud development.

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The possibility of using RAPD and AFLP methods for genetic monitoring of populations of Matthiola fragrans (Bunge), a species included in the Red Book of the USSR, was shown for the first time. An analysis of inter- and intrapopulation and interspecies genome polymorphism was performed. Differences in the genetic structure of Matthiola populations from various geographical collection points were revealed. A simple method of performing RAPD analysis and the great number of unique markers found in each population compared with the AFLP analysis, as well as the good division of populations under statistical treatment, allow us to draw the conclusion that using the RAPD method in genetic monitoring of rare and insufficiently studied species is well founded.

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IT is a remarkable fact that the disturbances connected with genic sterility in hybrids between species (or races) are paralleled within species by similar disturbances caused by single genes. For example, there is an analogy between the asynaptic mutations in several plants and genic asynapsis in hybrids and likewise between the polymitotic mutation in Zea and the spermatogenesis in Drosophila pseudo-obscura hybrids. Similarly, I have recently found a property analogous to the long-chromosome mutation in Matthiola in a grasshopper hybrid, the chromosomes of which also show a sort of ‘stickiness’ reminding one of the ‘sticky’ mutation in Zea1. Dobzhansky has several times directed attention to this parallelism2, though he does not seem to think it has any deeper genetical significance. In my opinion, there is, however, a possibility of putting the two phenomena on a common basis.

THE obituaries of Miss E. R. Saunders in Nature of August 18, 1945, while describing her morphological and educational work, do not refer to her contributions to genetics. These were, however, of the first importance. In 1897 she began experimental plant breeding at Cambridge in collaboration with Bateson, and the results were presented to the Evolution Committee of the Royal Society in 1901. Meanwhile Mendel's work had been rediscovered in 1900. By 1901 she had established the existence of Mendelian inheritance in Lychnis, Datura and Matthiola. It is clear that she and Bateson had independently rediscovered some at least of Mendel's laws before his work was known to them. She must in fact be regarded as the ‘mother’ of British plant genetics.

CHROMOSOMAL mutants with one extra chromosome (or the corresponding n + 1 gametes) have been found in Oenothera, Datura, Matthiola, Nicotiana, Uvularia, and perhaps Mirabilis. It seems probable that they could be found in many other plants, if investigation ad hoc were made, either as somatic or gametic mutations. Such 2n + 1 offspring have also been found fairly often in Drosophila, and doubtless occur in other animals.