The influence of the plasmotype on the regulation of the activity of L-phenylalanine ammonia-lyase (studies on Oenothera forms of the section Raimannia)

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Abstract
The regulation of the activity of L-phenylalanine ammonia-lyase (PAL) in seedlings of the complex heterocygotes Oenothera berteriana (with the chromosome complexes B and I) and Oenothera odorata (with the complexes v and I) and of their progeny was investigated. The following main results were obtained: The plasmotype (plasmon) has a significant effect upon the amount of increase of the activity of PAL during illumination with continuous far-red light (Figs. 2-5). Combined with the genotypes v.I, B.I and l.v the plasmotype of Oenothera berteriana effects a higher maximal activity after 20 hrs than the plasmotype of Oenothera odorata. This influence of the plasmon is constantly inherited. The influence of the chromosome complexes is characterized by the order I-v-l-B; the I-complex causes the highest, the B-complex the lowest increase in PAL-activity. Cytoplasm and plastids have no apparent influence either on the PAL-activity in darkgrown seedlings or on the amount of increase of PAL-activity which is brought about by wounding (Fig. 7). Therefore it can be concluded that the plasmotype affects very specifically the light-induced PAL-synthesis. There is no evidence so far for the existence of isoenzymes of PAL in the seedlings of Oenothera forms. Because of various correlations between light-induced PAL-activity and anthocyanin formation (Table 2), it can be supposed that the plasmon takes part in the regulation of anthocyanin formation by directing the PAL-activity. By the technique of simultaneous irradiation it is demonstrated that anthocyanin formation under continuous illumination with far-red is mediated by phytochrome (Fig. 6). The possibility of explaining the influence of the plasmotype of Oenothera forms on various phytochrome dependent reactions on the basis of a pleiotropic mechanism is discussed.