Phylogenetic age and relationship between Far East conifers as revealed by the comparison of their seed proteins.
The protein complex in the seeds of eight species of Far East conifers (Pinus koraiensis, Taxus cuspidata, Pinus densiflora, Abies holophylla, Taxus cuspidata, Microbiota decussata, Picea ajanensis and Larix kurilensis [L. kamtschatica]) was studied to estimate their phylogenetic age and relationship. Total protein content and the ratio between readily (RSP), moderately (MSP), and hardly (HSP) soluble proteins in the seeds were used as a criterion for phylogenetic advancement. Protein content in seeds varied from 10% of dry wt in Pinus koraiensis to 34% in Taxus cuspidata. Seeds of Pinus densiflora contained the greatest fraction of HSP (87%), which might indicate the ancient origin of this species; seeds of Abies holophylla had the greatest fraction of RSP (74%), which characterizes this species as the youngest. Relict bradytelic conifers (Taxus cuspidata, Microbiota decussata, and Pinus koraiensis) had a specific protein composition, which does not reflect their phylogenetic age. The narrow protein spectrum in Taxus cuspidata and Microbiota decussata might indicate their ancient origin. Common proteins in the seeds of Taxus cuspidata and other Pinaceae seem to indicate their relationship. Protein components found in the seeds of all the Pinaceae studied probably represent the phylogenetically old proteins typical of this family. It is concluded that the pattern and amount of protein in the seeds of Far East conifers are appropriate biochemical indicators of the relative phylogenetic age of particular genera. Relict species require additional morphological, anatomical, and biochemical criteria.