[The influence of the plasmotype on the regulation of the activity of L-phenylalanine ammonia-lyase (studies on Oenothera forms of the section Raimannia)].
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.
Institut für Biologie der Universität Tübingen, Tübingen, Deutschland.
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Hachtel