Quantitative and qualitative investigations on the seed proteins of mutants and recombinants of Pisum sativum.

The proteins of the seed flour of 26 X-ray induced mutants and 5 recombinants of the species Pisum sativum were analysed quantitatively and qualitatively. The values obtained were related to the seed yield of the genotypes In this way, the protein yield as well as the production of specific amino acids per genotype were determined. The following results were obtained. 1. The mean values for the character "total protein content of the seed flour" of the genotypes studied varied between 14 and 23%. The fasciated mutant 489C produced 18-23% more seed proteins than the initial line in three subsequent generations. The mean values of some other mutants and recombinants were 10-17% higher, the lowest value being 27% lower than that of the control values. In the material investigated there is no correlation between seed size and seed protein content. 2. The buffer-soluble seed proteins of 55 mutants were electrophoretically subdivided in different subfractions and the protein patterns were determined. They are extraordinarily variable. Distinct groups of mutants do not only differ from the initial line but also from one another with regard to the number, position and breadth of their bands. A correlation between the degree of morphological deviations of specific genotypes and the composition of their seed proteins was not observed. Moreover, differences in the concentration of specific protein fractions between the genotypes were densitometrically ascertained. 3. The globulins and albumins of some genotypes were quantitatively determined and electrophoretically subdivided into subfractions which differ between different mutants with regard to their number as well as their concentration. This is especially valid for the albumins which could be essentially stronger subdivided than the globulins. 4. The amino acid spectra of all the mutants investigated agree qualitatively with the spectrum of the initial line, however, clear quantitative differences in distinct amino acids were observed. The proportion of the essential amino acids is increased in two mutants by 5 and 20% in relation to the control line. 5. The protein production of the fasciated mutant 489C was 20-70% higher than the corresponding values of the initial line in three subsequent generations regarding its high seed production. The protein yield of the early flowering mutant 46C was about 20% lower and that of the bifurcated mutant 1201A 12-31% higher as related to the initial line. Mutant 1201A shows an equally favourable situation with regard to the total content of the essential amino acids. Its lysine production exceeded the control values by 20-40%. 6. The different components of the protein synthesis can negatively be influenced by the co-operation of the mutant genes. The protein production per plant, the total production of essential amino acids as well as the lysine production are lower in the recombinants 68C/176A and 68C/1201A as compared to the parental mutants. The combination of genes 68C and 46C does not show any negative interactions.